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VAL.ITABL.E  MEDICAL,  BOOKS, 


PUBLISHED    BY 


GRIGG    <£   ELLIOT, 

JM>.  9  JYorth  Fourth  Street, 


PHILADELPHIA. 


The  DISPENSATORY  of  the  UNITED  STATES:  consisting  of, 
1st,  A  TREATISE  ON  MATERIA  MEDICA,  or  the  Natural, 

Commercial,  Chemical,  and  Medical  History  of  the  Substances  employed  in  Medicine. 

2d,  A  TREATISE  ON  PHARMACY:  comprising  an  account  of 

the  preparations  directed  by  the  American  and  British  Pharmacopoeias,  and  designed 
especially  to  illustrate  the  Pharmacopoeia  of  the  United  States.  By  George  B.  Wood, 
M.  D.,  Professor  of  Materia  Medica  and  Pharmacy  in  the  Philadelphia  College  of  Phar- 
macy ;  and  Franklin  Bache,  M.  D.,  Professor  of  Chemistry  in  the  College  of  Pharmacy 
and  in  the  Franklin  Institute. 

The  above  is  one  of  the  most  valuable  Works  of  the  kind  ever  issued  from  the  Ame- 
rican Press. 

One  among  the  most  distinguished  of  tue  Medical  faculty,  in  noticing  the  great  value 
of  this  work  to  the  student  and  practitioner,  says,  "  We  therefore  hailed  with  no  incon- 
siderable pleasure  the  appearance  of  the  Dispensatory  of  the  United  States,  convinced 
from  our  knowledge  of  its  authors  that  it  would  prove  a  most  valuable  addition  to  our 
Medical  literature.  We  have  not  been  disappointed  in  these  expectations,  and  feel 
fully  persuaded  that  it  will  take  the  first  rank  among  works  of  this  character." 

The  editors  of  the  Journal  of  Pharmacy  observe,  as  regards  the  merits  of  the  work, 
"We  recommend  it  most  cordially  to  the  Medical  fraternity,  to  the  practical  pharma- 
ceutist, and  especially  to  the  diligent  perusal  of  the  student  of  medicine  or  pharmacy." 

We  cannot  refrain  from  expressing  our  firm  conviction,  that,  as  a  whole,  this  Dispen- 
satory is  the  best  work  in  the  English  language,  on  the  subjects  of  which  it  treats;  and 
we  know  of  no  work  so  well  calculated  in  the  eyes  of  our  neighbours  of  Europe  to 
raise  the  character  of  American  science. 

COOPER'S  FIRST  LINES  op  the  PRACTICE  op  SURGERY: 

designed  as  an  introduction  for  students,  and  a  concise  book  of  reference  for  practitioners. 
By  Samuel  Cooper,  M.  D.  With  Notes,  by  Alexander  H.  Stevens,  M.  D.,  and  additional 
Notes,  and  an  Appendix,  by  Dr.  S.  M'Clellan.  Third  American,  from  the  last  London 
edition,  revised  and  corrected.   With  several  new  plates  and  wood  cuts,  in  2  vols.  8vo. 

This  work  is  highly  esteemed  by  all  the  distinguished  of  the  Medical  Profession  ;  and, 
in  many  of  our  Medical  Schools,  is  used  as  a  Text  Book. 

EBERLE'S  PRACTICE  OF  MEDICINE.— A  Treatise  on  the 

Theory  and  Practice  of  Medicine,  in  2  vols.  8vo.  By  John  Eberle,  M.  D.  Professor  of 
Materia  Medica  and  Obstetrics  in  the  Jefferson  Medical  College,  Philadelphia,  2d  edi- 
tion, improved. 

This  is  one  of  the  most  valuable  works  on  the  Practice  of  Medicine,  that  has  ever 
issued  from  the  American  or  English  Press. 

The  distinguished  editor  of  the  North  American  Medical  and  Surgical  Journal,  speak- 
ing  of  this  work,  says, — "The  work  of  Dr.  Eberle  is  confessedly  one  of  very  great 
merit.  It  does  much  credit  to  his  industry  and  learning,  while  it  places  in  a  yery  fa- 
vourable point  of  view  his  abilities  as  a  practitioner.  The  talents,  industry,  and  variety 
of  research  necessary  for  the  production  of  a  system  of  Practical  Medicine,  are  possess- 
ed by  few,  and  when  we  say,  as  we  do  with  great  candour,  that  the  Treatise  before  us 
will  bear  a  very  favourable  comparison  with  any  modern  work  of  the  same  class,  while 
it  is  far  superior,  as  well  in  regard  to  the  soundness  of  its  pathological  views,  generally 
speaking,  as  to  the  excellence  of  its  therapeutic  precepts,  to  the  more  popular  of  the 
English  systems,  we  confer  upon  it  and  its  author  no  mean  praise." 

The  April  No.  of  Johnson's  London  Medico-Chirurgical  Review,  speaking  of  this 
work  observes,  "  That  this  is  a  very  respectable  compilation ;  in  fine,  superior  to  Tho- 
mas's Practice  of  Physic  in  this  country." 

Although  designed  chiefly  for  professional  men,  it  will  be  found  a  valuable  practical 
manual  for  private  or  domestic  reference.    If  heads  of  families  were  to  purchase  and 


MEDICAL  WORKS. 


consult  this  work  instead  of  the  empirical  and  in  many  respects  misleading  compounds 
so  common,  they  would  have  the  satisfaction  of  being  assured,  that  nothing  but  sound 
and  well  tested  practical  directions  would  be  offered  them, — at  the  same  time  they 
■would  acquire  correct  notions  concerning  the  character  and  systems  of  diseases.  Every 
person  of  good  understanding  may  comprehend  the  practical  rules  laid  down  in  this  work. 
To  render  this  invaluable  work  particularly  useful,  as  a  work  of  reference  for  family 
use,  a  glossary  is  added  of  the  technical  terms  used  in  the  work. 

A  TREATISE  OX  THE  MATERIA  MEDICA  and  THERA- 

PEUTICS,  in  2  vols.  Third  edition,  improved  and  greatly  enlarged.  By  John  Eberle, 
M.  D.,  Professor  of  Materia  Medica  and  Obstetrics  in  the  Jefferson  Medical  College ; 
Member  of  the  American  Philosophical  Society;  Corresponding  Member  of  the  Medico- 
Chirurgical  Society,  &.c. 

THE  PHARMACOPOEIA  of  the  United  States,  revised  edition, 

bv  authority  of  the  National  Medical  Convention,  which  met  in  Washington,  in  January, 
1830,  in  1  vol.  Svo. 

All  persons  ordering  this  work  will  please  say  "  The  Philadelphia  edition  of  1831." 

To  all  country  Practitioners  and  Apothecaries,  a  copy  of  this  work  is  indispensable ; 
not  one  dose  of  medicine  should  be  put  up  unless  by  the  prescriptions  contained  in  it. 
The  government  has  taken  a  full  supply  for  the  Medical  Staff  of  the  Army  and  Navy  of 
the  United  States. 

Resolved,  As  the  opinion  of  the  Philadelphia  College  of  Physicians,  and  the  Phila- 
delphia College  of  Pharmacy,  that  the  United  States  Pharmacopoeia  of  1830,  as  revised 
by  the  National  Medical  Convention  which  met  at  Washington,  in  January,  1830,  de- 
serves the  confidence  of  the  Medical  and  Pharmaceutical  Professions;  and  for  the  pur- 
pose of  promoting  uniformity  in  Pharmaceutical  formula:,  the  two  Colleges  do  agree  to 
adopt  the  said  work  as  a  standard  of  Pharmacy,  and  recommend  to  their  respective 
members  to  conform  to  its  directions. 

THOMAS  PARKE,  President  of  the  College  of  Physicians. 
DANIEL  B.  SMITH,  President  of  the  College  of  Pharmacy. 

Philadelphia,  March,  1832. 

VELPEAU'S   ELEMENTARY    TREATISE  OX  THE  ART 

OF  MIDWIFERY,  or  the  Principles  of  Toxicology  and  Embryology,  in  1  volume,  Svo. 
Translated  from  the  French,  by  Charles  D.  Meigs,  M.  D.  Member  of  the  College  of 
Physicians,  Sec.  &c. 

The  distinguished  editors  of  the  North  American  Medical  and  Surgical  Journal,  after 
noticing  the  various  works  on  the  subject  of  the  obstetric  art,  observe:  "We  have 
chosen  this,  because  it  appears  to  us  to  be  one  of  the  very  best.  It  is  a  model  for  such  a 
work: — the  several  parts  being  duly  connected,  and  related  and  managed  with  a  beautiful 
simplicity  and  dexterity,  like  that  used  by  the  naturalist.  A  sort  of  nomenclatural  neatness 
and  conciseness  reigns  throughout."    It  is  a  book  that  no  physician  should  be  without. 

A  TREATISE  OX  THE  ANATOMY,  PHYSIOLOGY,  AND 

DISEASES  OF  THE  BONES  AND  JOINTS.  In  1  vol.  Svo.  By  S.  D.  Gross,  M.  D. 

MANUAL  OF  GEXERAL  AXATOMY,    containing  a  concise 

description  of  the  Elementary  Tissues  of  the  Human  Body.  From  the  French  of  A.  L. 
Bayle  and  H.  Hollard.   By  S.'  D.  Gross,  M.  D. 

This  volume  has  been  highly  approved  by  many  of  the  principal  medical  men,  and 
has  been  recommended  by  several  anatomical  teachers.  "  We  recommend  this  little 
volume  to  the  anatomical  student;  it  contains  an  excellent  account  of  the  primitive  tis- 
sues, and  will  greatly  facilitate  a  knowledge  of  what  has  been  too  much  neglected  in 
this  country,  general  anatomy." — Medical  Gazette. 

MANUAL  of  the  ELEMENTS  or  OPERATIVE  SURGERY: 

arranged  so  as  to  afford  a  concise  and  accurate  description  of  the  present  state  of  the 
Science  in  Paris.  From  the  French  of  A.  Tavernier,  Doctor  of  Medicine  of  the  Faculty 
of  Paris,  late  Surgeon  to  the  3d  regiment  of  artillery,  Stc.  kc.  &c.  By  S.  D.  Gross,  M.  D. 

MANUAL  OF  PRACTICAL  OBSTETRICS:  arranged  so  as  to 

afford  a  concise  and  accurate  description  of  the  management  of  Preternatural  Labours; 
preceded  by  an  account  of  the  Mechanism  of  Natural  Labour.  From  the  French  of  Ju- 
lius Hutin,  Doctor  of  Medicine  of  the  Faculty  of  Paris,  Professor  of  Obstetrics,  and  of 
the  diseases  of  women  and  children,  &c.  &c.  Sec.   By  S.  D.  Gross,  M.  D. 


MEDICAL  WORKS. 


Armstrong's  Medical  Works. 
Armstrong-  on  Typhus  Fever. 
Armstrong  on  Consumption,  Puerperal  Fe- 
ver, &c. 
Arnott's  Physics,  2  vols.  8vo. 
Abercrombie  on  the  Brain,  8vo. 
Abercrombie  on  the  Stomach,  8vo. 

Broussais'  Phlegmasia,  2  vols. 

Boisseau  on  Fevers. 

Burns's  Anatomy  of  the  Head  and  Neck. 

Bell  on  Baths. 

Bell  on  Wounds. 

Beclard's  General  Anatomy. 

Bichat   on  Pathology. — This   posthumous 

work  of  Bichat  on  Pathological  Anatomy, 

is  one  of  much  value  and  interest  to  the 

student  of  pathology. 
Buchan's  Domestic  Medicine,  improved. 
Bell  on  the  Arteries,  coloured  plates. 
Bell's  Anatomy,  new  edition. 
Bancroft  on  Fever. 
Blackall  on  Dropsies,  new  edition. 
Bateman's  Synopsis  of  Cutaneous  Diseases, 

8vo. 
Bell  on  Teeth,  8vo. 
Belliol  on  Herpetic  Affections. 

Cooper's  Lectures,  by  Tyrrell. 
Cook's  Morgagni. 
Colles's  Surgical  Anatomy. 
Cannaras  on  Health. 

Cooper's  Surgical  Dictionary,  2  vols.  8vo. 
Coster's  Manual  of  Surgical  operations. 
Cooper's  Lectures  on  Surgery. 
Calhoun's  Prout  on  the  Urinary  Organs. 
Cazenave  ou  Diseases  of  the  Skin. 


Daniel  on  Fevers. 

Desault's  Surgical  Works. 

Duffin  on  the  Spine,  12mo. 

De  La  Beche's  Geological  Manual. 

Domestic  Medicine. 

Elliot's  Botany  of  South  Carolina,  2  vols. 

8vo. 
Eaton's  Manual  of  Botany,  12mo. 

Faraday's  Chemical  Manipulation. 

Good's  Study  of  Medicine,  5  vols.   8vo., 

new  edition. 
Good's  Book  of  Nature,  8ro. 
Gross's  Manual  of  General  Anatomy,  8vo. 
Gross  on  the  Bones  and  Joints,  8vo. 
Gross's  Manual  of  Obstetrics,  12mo. 
Graham  on  Indigestion,  8vo. 
Gooch  on  Women. 
Gooch  on  Midwifery. 

Hamilton  on  Purgatives,  8vo. 

Hooper's  Examinations,  new  edition,18mo. 

Hutin's  Physiology. 


Hooper's  Medical  Dictionary,    8vo.,   new 

edition. 
Henning's  Military  Surgery,  8vo. 
Hall  on  Loss  of  Blood,  8vo. 
Hufeland  on  Scrofulous  Diseases.  1  vol. 

Johnson  on  the  Liver  and  Internal  Organs, 

8vo. 
James's  Burns,  2  vols.  8vo. 
Johnson  on  Change  of  Air. 

Laennec  on  the  Chest,  8vo. 

London  Practice  of  Midwifery,  8vo. 

Lawrence's  Lectures  on  Physiology,  Zo- 
ology, and  the  Natural  History  of  Man, 
8vo." 

Laennec  on  the  Stethoscope. 

Lobstein  on  the  Eye. 

Macculloch  on  Fevers,  8vo. 

Manual  of  Surgical  Anatomy.  By  Edwards, 

12mo. 
Martinett's  Therapeutics,  18mo. 
Manual  for  the  Stethoscope,  12mo. 
Murray's  Materia  Medica,  new"  edition,  8vo. 
Macculloch  on  Remittent  and  Intermittent 

Diseases. 
Macculloch  on  Malaria. 
Martinet's  Manual  of  Pathology. 

Nuttall's  Introduction  to  Botany,  870. 

Orfila  on  Poisons. 

Paris's  Pharmacologia,  a  new  edition,  8vo. 

Paris  on  Diet,  8vo. 

Phillips  on  Indigestion,  8vo. 

Phillips  on  Acute  and  Chronic  Diseases,  8vo. 

Parsons's  Anatomical  Preparations. 

Porter's  Chemistry  of  the  Arts,  2  vols. 

Richerand's  Physiology,  new  edition. 
Rush  on  the  Mind,  new  fine  edition. 
Ratier's  Formulary,  18mo. 

Smith  on  Fevers,  8vo. 

Scudamore  on  Gout,  8vo. 

Saifsy  on  the  Ear,  8vo. 

Surgeon  Dentist's  Manual,  18mo. 

Stevenson  on  the  Eye. 

Smith  &  Tweedie  on  Fevers. 

Symes's  Surgery. 

Snell  on  the  Teeth. 

Smith  on  the  Arteries. 

Select  Medical  Transactions. 

Thompson's  Chemistry,  4  vols. 

Thomas's  Domestic  Medicine,  8vo. 

Thompson  on  Inflammation,  8vo. 

Tweedie  on  Fever,  8vo. 

Tate  on  Hysteria,  8vo. 

Teale  on  Neuralgic  Diseases,  8vo. 

Williams  on  the  Lungs,  8vo. 
Wistar's  Anatomy,  2  vols. 


MEDICAL   WORKS. 


TURNER'S  ELEMENTS  OF  CHEMISTRY;  including  all  the 

recent  discoveries  and  doctrines  of  the  Science,  to  the  present  time.  In  1  vol.  12mo. 
By  Edward  Turner,  M.  D.  F.  R.  S.  E.,  &c.  &.c. ;  with  important  corrections,  by  F.  Bache, 
M.  D.  Fourth  edition. 

This  work  is  particularly  adapted  for  the  higher  classes  in  colleges,  academies,  &c. 
It  is  held  in  the  highest  estimation  in  Europe,  and  has  been  adopted  as  a  Text  Book  in 
many  of  our  celebrated  medical  schools.  The  Author  ranks  with  the  most  distinguished 
of  the  Scottish  savans. 

HIND'S  VETERINARY  SURGEON,  or  Farriery  taught  on  a 

new  and  easy  plan,  being  a  treatise  on  all  the  diseases  and  accidents  to  which  the  horse 
is  liable.  With  considerable  additions  and  improvements,  adapted  particularly  to  this 
country,  by  Thomas  M.  Smith,  Veterinary  Surgeon,  and  member  of  the  London  Vete- 
rinary Medical  Society,  in  1  vol.  12mo. 

The  publisher  has  received  numerous  flattering  notices  of  the  great  practical  value 
of  this  work.  The  distinguished  editor  of  the  American  Farmer,  speaking  of  the 
work,  observes — "  We  can  not  too  highly  recommend  this  book,  and  therefore  advise 
every  owner  of  a  horse  to  obtain  it." 

CONVERSATIONS  ON  CHEMISTRY,  in  which  the  Elements 

of  that  Science  are  familiarly  explained  and  illustrated  by  Experiments  and  Engravings 
on  wood.  From  the  last  London  edition.  In  which  all  the  late  Discoveries  and  Im- 
provements are  brought  up  to  the  present  time,  by  Dr.  Thomas  P.  Jones. 

All  preceptors  who  have  a  sincere  desire  to  impart  a  correct  knowledge  of  this  im- 
portant science  to  their  pupils,  will  please  examine  the  present  edition,  as  the  correc- 
tion of  all  the  errors  in  the  body  of  the  work  renders  it  very  valuable. 

The  eminent  Professor  Bigelow  of  Harvard  University,  in  noticing  this  work,  ob- 
serves, "lam  satisfied  that  it  contains  the  fundamental  principles  and  truths  of  that 
Science,  expressed  in  a  clear,  intelligible,  and  interesting  manner.  The  high  charac- 
ter of  the  author,  as  a  lecturer,  and  as  a  man  of  Science,  will,  I  doubt  not,  secure  for 
the  work  the  good  opinion  of  the  public,  and  cause  its  extensive  adoption  among  Se- 
minaries and  Students." 


Dr.  Pattison's  Lecture. 

Dr.  Baudelocque  on  Puerperal  Peritonitis. 

Miner  &  Tully  on  Fever. 

The  Physician's  Pocket  Synopsis,  by  Bart- 
let. 

Brown's  Elements  of  Medicine. 

Gregory's  Practice. 

Ducamp  on  Retention  of  Urine,  &c. 

Denman's  Midwifery. 

Desruelles  &  Guthrie  on  Venereal  Dis- 
ease. 

Dr.  Dewees's  Medical  Works. 

Dr.  Horner's  Medical  Works. 

Larrey's  Surgical  Memoirs. 

Ryan's  Medical  Jurisprudence. 

Manual  of  Materia  Medica. 

Dr.  Rush  on  the  Voice. 

Cooper  on  Dislocations. 

The  Ladies'  Medical  Guide,  by  Reese. 

Maygrier's  Anatomy. 

Lincoln's  Botany. 


Lind  on  Hot  Climates. 

M'Clean  on  Hydrothorax. 

Hildebrand  on  Typhus. 

Cavalos's  Philosophy. 

Jones's  edition,  Conversations  on  Chemis- 
try. 

Jones's  Conversations  on  Natural  Philo- 
sophy. 

Brand's  Chemistry. 

The  Medical  Pocket  Book. 

Rush's  Hillary. 

Willan  on  the  Skin. 

Bostock's  Physiology. 

Cloquet's  Anatomy. 

Comstock's  Mineralogy. 

Shepard's  Mineralogy. 

Various  work  on  Cholera. 

The  Nurse's  Guide. 

Broussais's  Pathology. 

Broussais's  Physiology. 


%*  Ml  the  new  Medical  works  received  and  for  sale  as  soon  as  published,  on  the  most 
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for  sale  by  J.  Grigg,  No.  9,  N.  Fourth  Street. 

MEDICAL,  CHEMICAL,  BOTANICAL,  &c. 


Averil's  Surgery. 

Abernethy's  Surgical  works,  com- 
plete. 

Armstrong  on  Typhus  Fever. 

Barton's  Botany  and  Flora. 

Bostoek's  Physiology. 

Bell  on  the  Nerves. 

Buchan's  Domestic  Medicine. 

Bell  on  the  Muscles,  col'd  plates. 

Bichat's  Anatomy,  4  vols. 

Bell's  Surgery. 

Brown's  Elements. 

Bateman's  Synopsis. 

Bell  on  Wounds. 

Bell's  Dissection. 

Burns  on  Inflammation. 

Bell  on  the  Venereal. 

Blumenbach's  Physiology. 

Bichat's  Treatise  on  the  Mem- 
branes in  general. 

Beyer's  Surgery,  2  vols. 

Blackall  on  Dropsies. 

Blane's  Medical  Logic. 

Bichat's  Pathological  Anatomy. 

Cooper,  Sir  A.  on  Fractures  and 
Dislocations. 

Cook  on  Nervous  Diseases. 

Cooper  and  Travers'  Surgical  Es- 
says. 

Chapman's  Medical  Journal,  com- 
plete. 

Coster's  Manual  of  Surgical  Opera- 
tions. 

Caldwell's  Cullen. 

Chapman's  Therapeutics  and  Ma- 
teria Medica. 

Charmichael  on  Venereal,  new  edi- 
tion. 

Combe's  Phrenology. 

Cooper's  Lectures  on  Surgery, 
8vo.  new  edit. 

Cooper's  Dictionary  of  Practical 
Surgery,  with  Notes  by  Dr.  Wil- 
liam Anderson,  a  new  edit.  2 
vols.  8vo. 

Clark  on  the  Diseases  of  Women. 

Dewees'  Midwifery. 

on  Children. 

Essays  on  Midwifery. 

on  Females. 

Duncan  on  Consumption. 

Duncan's  Midwifery,  by  Francis. 


Dewees  on  Parturition. 

Eclectic  Repertory,  10  vols. 

Ewell's  Medical  Companion. 

Ferriar's  Medical  Reflections. 

Gibson's  Surgery. 

Gregory's  Dissertations  on  Climate. 

Mailer's  Anatomical  Description  of 
the  Arteries. 

Hunter  on  the  Blood. 

Henry's  Chemistry,  3  vols. 

Hamilton  on  Purgatives. 

Hunter  on  Venereal. 

Hooper's  Medical  Dictionary. 

Horner's  Anatomy. 

Johnson  on  the  Liver  and  internal 
Organs. 

James's  Burns. 

Laennec  on  the  Chest. 

Magendie  on  Prussic  Acid. 

Murray's  Materia  Medica  and  Phar- 
macy. 

Paris's  Medical  Chemistry. 

Park's  Chemical  Catechism. 

Potts'  Surgery,  2  vols. 

Paris's  Pharmacalogia,  new  ed. 

Richerand's  Physiology. 

Jones  on  Hemorrhage. 

Saunders  on  the  Eye. 

Thomas's  Practice,  new  ed. 

Thatcher's  Dispensatory  and  Prac- 
tice. 

The  Edinburgh  Dispensatory. 

The  Study  of  Medicine  and  Noso- 
logy, by  J.  M.  Good,  5  vols. 

Thomas's  Domestic  Medicine. 

Underwood  on  the  Diseases  of 
Children. 

Ure's  Chemical  Dictionary,  2  vols. 

Comstock's  Mineralogy. 

Bell's  Anatomy,  new  ed. 

Brand's  Chemistry. 

The  Eclectic  &  General  Dispensa- 
tory.    A  new  work. 

Elliott's  Botany,  2  vols. 

Smith's  Grammar  of  Botany. 

Good's  Book  of  Nature. 

Rush  on  the  Mind.  A  new  edition 
of  this  invaluable  book  just  pub- 
lished. 

All  the  new  Medical  works  receiv- 
ed and  for  sale  as  soon  as  pub- 
lished. 


J.  GRIGG 

Has  in  Press  and  will  speedily  publish, 

A 

MANUAL  OF  PRACTICAL   OBSTETRICS: 
Arranged  so  as  to  afford  a  Concise  and  Accurate  Descrip- 
tion of  the  Management  of  Preternatural  Labours; 
PRECEDED  BY  AN  ACCOUNT 

OF  THE 

3IECHAMS3I  OF  XATURAL  LABOUR. 

FROM  THE  FREXCH  OF 

JULES  HATIN, 

Doctor  of  Medicine  of  the  Faculty  of  Paris,  Professor  of 

Obstetrics  and  of  the  Diseases  of  Women  and 

Children,  &.c.  &c.  &c. 

BY  S.  D.  GROSS,  M.  D. 


MANUAL 


GENERAL  ANATOMY, 


CONTAINING 


A  CONCISE  DESCRIPTION  OF  THE  ELEMENTARY  TISSUES 


HUMAN  BODY. 


mCO!  THE  FBENCH  OF 

A.  L.  J.  BAYLE  and  H.  HOLLARD. 

BY 

S.  D.  GROSS,  M.  D. 


PHILADELPHIA: 
JOHN  GRIGG,  NO.   9,  NORTH  FOURTH  STREET. 

182S. 


Eastern  District  of  Pennsylvania,  to  wit: 

BE  IT  REMEMBERED,  that  on  the  twenty-seventh  day  of  Septem- 
ber, in  the  fifty-third  year  of  the  Independence  of  the  United  States  of 
America,  A.  D.  1828,  J.  Grigg  of  the  said  district  hath  deposited  in 
this  office  the  title  of  a  book,  the  right  whereof  he  claims  as  proprietor 
in  the  words  following,  to  wit: 

"A  Manual  of  General  Anatomy,  Containing  a  Concise  Description 
of  the  Elementary  Tissues  of  the  Human  Bodv.  From  the  French 
of  A.  L.  J.  Bayle  and  H.  Hollard.     By  S.  D.' Gross,  M.  D." 

In  conformity  to  the  act  of  the  Congress  of  the  United  States,  entitled 
"  An  act  for  the  encouragement  of  learning,  by  securing  the  copies  of 
maps,  charts,  and  books  to  the  authors  and  proprietors  of  such  copies 
during  the  times  therein  mentioned;" — And  also  to  the  act  entitled 
"An  act  supplementary  to  an  act  entitled  'An  act  for  the  encourage- 
ment of  learning  by  securing  the  copies  of  maps,  charts,  and  books  to 
the  authors  and  proprietors  of  such  copies  during  the  times  therein 
mentioned,5  and  extending  the  benefits  thereof  to  the  arts  of  designing, 
engraving,  and  etching  historical  and  other  prints." 

D.  CALDWELL. 
Clerk  of  the  Eastern  District  of  Pennsylvania. 


Hkkrfcal  CoHccSon 


TO 

GEO.  M'CLELLAN,  M.  D. 

PROFESSOR  OF  ANATOMY  AND  SURGERY 

I3J  THE 

JEFFERSON  MEDICAL  COLLEGE, 

Whose  great  skill  and  extensive  knowledge  in  the  va- 
rious  departments  of  the  Medical  Sciences,  add  lustre  to 
the  profession,  and  whose  integrity  of  principle  and  pri- 
vate virtues  are  not  less  distinguished  than  his  professional 
attainments,  the  following  pages  are  inscribed  as  a  testi- 
mony of  the  esteem,  the  gratitude  and  respectful  attach- 
ment of  his  friend  and  pupil, 

S.  D.  GROSS. 

Philadelphia,  August,  1828. 


The  Reader  is  requested  to  correct  the  folloiuing 

ERRATA. 

Page.  Line. 

2,  30,  for  lymph,  read  chyle. 

9,  1,  for  spungy,  read  spongy. 

17,  5,  for  anasarca  and  oedema,  read  oedema  and  anasarca. 

19,  10,  for  recrementitial,  read  excrementitial. 

31,  7,  for  carachus,  read  urachus. 

84,  10,  for  consists,  read  consist. 

86,  11,  for  desication,  read  desiccation. 

120,  24,  for  vertebra,  read  vertebrae. 

163,  28,  for  on  dividing  of  the  ganglia,  read  on  division  of  the 
ganglia. 


PREFACE. 


General  Anatomy  is  a  science  of  comparatively  modern 
date;  and  like  every  other  great  and  important  improve- 
ment, it  has  gradually  arrived  at  its  present  degree  of  per- 
fection. To  Bichat,  no  doubt,  is  due  the  honour  of  having 
first  established  this  branch  of  anatomy  into  a  science,  and 
the  work  which  he  has  left  us  upon  this  subject,  is  at  once 
an  imperishable  monument  of  his  great  talents  and  of  his 
ingenious  and  profound  researches. 

Notwithstanding  the  importance  of  a  thorough  know- 
ledge of  General  Anatomy,  it  is  a  fact,  that  it  has  received 
less  attention  in  this  country,  than  perhaps  in  any  other 
part  of  the  globe  to  which  medical  science  has  hitherto 
found  its  way.  For  the  truth  of  this  assertion,  we  appeal 
to  the  candid  and  high" minded  student,  whether  during 
the  course  of  his  attendance  upon  lectures,  he  has  heard 
his  anatomical  professor  enter  into  any  minute  details  on 
this  important  branch  of  his  professional  studies,  or  whether 
he  has  not  merely  glanced  at  it,  or  perhaps  said  nothing 
upon  the  subject.  We  shall  not  stop  to  inquire  into  the 
cause  of  this  neglect;  but  we  fondly  anticipate  the  day 
when  this  evil  shall  be  remedied;  and  ardently  hope  that 
the  science  of  general  anatomy  may  soon  receive  that  share 
of  attention  from  the  physicians  of  this  country,  which  it 
so  justly  merits,  and  which  it  at  present  receives  in  the 
medical  schools  of  Europe,  and  particularly  in  those  of 
France  and  Germany. 


VI  PREFACE. 

We  have  been  aware  that  a  work  on  general  anatomy  is 
much  wanted  in  this  country;  and  with  these  impressions 
we  have  undertaken  the  translation  of  the  Manual  of  MM. 
Bayle  and  Hollard;  in  doing  which  we  have  not  scrupled 
to  make  a  few  alterations,  but  the  deviations  from  the 
original  are  trifling.  If,  however,  we  have  failed  in  some 
instances,  in  doing  justice  to  the  original,  we  ask  only 
the  indulgence  of  those  who  have  the  liberality  and  can- 
dour to  receive  with  impartiality  whatever  is  intended  to 
facilitate  the  progress  of  their  studies,  while  we  neither 
ask  nor  care  for  the  indulgence  or  liberality  of  sentiment 
of  those  of  an  opposite  character. 

S.  D.  GROSS. 


INDEX. 


Page. 

Dedication,            -            -                    ,    -            -  -  -      iii 

Pheface,      -             -             -              -             -              -  -  "  -        y 

INTRODUCTION,  --....-X 

CHAPTER  I. 

Celluxab.  System,  -  -  -  -  ...       9 

Section  1.  Cellular  tissue,  properly  so  called,  -  -      ib. 

Pathological  Anatomy,               -  -  -      16 

Bibliography,     -            .            -  -  -     19 

Section  2.  Adipose  tissue,               -            -            -  -20 

Pathological  Anatomy,               -  -  -      24 

Bibliography,    -             -             -  -  -      25 
1 

.       CHAPTER  H. 

Vascuiar  System,              -            -            -            -  -  -      26 

Section  1.  General  Observations,  -  ib. 

Pathological  Anatomy,              -  -  -      31 

Section  2.  Of  the  Arteries,              -            -  -  -      32 

Pathological  Anatomy,              -  -  -      38 

SectionS.  Of  the  Capillary  vessels,            -  -  -      42 

Pathological  Anatomy,              -  -  -      47 

Section  4.  Of  the  Veins,     -            -            -  -  -      49 

Pathological  Anatomy,              -  -  -55 

Section  5.   Of  the  Lymphatic  System,        -  -  -57 

1.  Of  the  Lymphatic  vessels,    -  -  -     ib. 

2.  Of  the  Lymphatic  Ganglia,  -  -  -  63 
Pathological  Anatomy,  -  -  -  64 
Bib liography  of  the  Vascular  System,  -  -      6j 


VI 11  INDEX. 

CHAPTER  III. 

Of  tub  Ssnoca  Ststkh,      -            -            -            -            -  -  68 

Section  1.   General  Observations,   -             -  -  ib. 

Pathological  Anatomy,               -             -  71 

Section  2.   Of  the  Sero-splanchnic  Membranes,      -  -  74 

Pathological  Anatomy,               -             -  -  77 

Section  3.  Of  the  Synovial  Membranes,      -             -  -  ib. 

Pathological  Anatomy,               -             -  -  81 

Bibliography  of  the  Serous  System,     -  -  82 

CHAPTER  IV. 

Of  the  Fibrous  System,   -             -             -             -             -  -  84 

First  Division. 

Of  the  Fibrous  System,  properly  so  called,      -  ib. 

Section  1.  General  Observations,    -  ib. 

Pathological  Anatomy,              -            -  -  87 
Section  2.  Of  the  organs  composing  the  Fibrous  System, 

properly  so  called,        -             -             -  -  88 

Article  1.  Of  the  Fibrous  Ligamentous  organs,  -  ib. 

§  1.  Of  the  Ligaments,       -  ib. 

§2.  Of  the  Tendons,         -            -  -  90 

Article  2.   Of  the  Fibrous  Envelopes,             -  -  92 

§  1.  Aponeurotic  Envelopes,         -  -  ib. 

§  2.  Of  the  Tendinous  Sheaths,     -  -  93 

§3.  Of  the  Periosteum,     -            -  -  94 

Pathological  Anatomy,       -             -  -  95 

§  4.  Perichondrium,           -             -  -  96 
§  5.   Of  the  Fibrous  Envelopes  of  the  brain, 
the  Spinal  Marrow,  and  some  other 

organs,       ....  ib. 
§  6.   Of  the  Fibro-serous,  and  the  Fibro- 

mucous  Membranes,               -  -  97 

Second  Division. 

Yellow  elastic  Fibrous  System,             -  -  98 

Pathological  Anatomy,              -             -  99 

Third  Division. 

Fibro-cartilaginous  System,      -  -  ib. 

Pathological  Anatomy,              -             -  -  101 

Bibliography  of  the  Fibrous  System,   -  -  102 


INDEX.  IX 
CHAPTER  V. 

Cartilaginous  Sistem,     ------  103 

Section  1.  General  Observations,  -         —         "-,-  ib. 

Pathological  Anatomy,              -  105 

Section  2.  Articular  Cartilages,      ...            -  106 

Pathological  Anatomy,              -            -            -  108 

Section  3.  Perichondroidal  Cartilages,       -            -            -  109 

Pathological  Anatomy,              -            -            -  110 

Bibliography  of  the  Cartilaginous  system,         -  111 

CHAPTER  VI. 

Of  the  Osseous  System,    ------  112 

Section  1.  Of  the  Bones,    -            -            -            -  ib. 

Article  1.  General  Observations,        -            -            -  ib. 
Article  2.  Of  the  long,  broad,  short,  and  mixed  bones, 

in  particular,      -  122 

§  1.  Of  the  long  Bones,     -            -            -  ib. 

§2.  Of  the  broad  or  flat  Bones,    -            -  125 

§3.  Of  the  short  Bones,    -            -            -  127 

§4.  Of  the  mixed  Bones,              -            -  128 

Pathological  Anatomy,      -            -            -  ib. 

Section  2.  Of  the  Articulations  of  the  Bones,         -            -  136 

Pathological  Anatomy,              ...  140 

Bibliography  of  the  Osseous  System.    -            -  142 

CHAPTER  Vn. 

Of  the  Nervous  System,  ------  144 

Section  1.  General  Observations,   -  ib. 

Section  2.  Of  the  Nervous  Centres,           -            -            -  154 

Article  1.  Of  the  Cerebro-spinal  Centre,        -            -  ib. 

Pathological  Anatomy,       -  160 

Article  2.  Of  the  Nervous  Ganglia,    -            -            -  162 

Section  3.  Of  the  Nerves,  -----  167 

Article  1.  Of  the  Cerebro- Spinal  nerves,       -            -  ib. 

Pathological  Anatomy,       -            -            -  173 

Article  2.  Of  the  Ganglionic  Nerves,            -            -  175 

Pathological  Anatomy,     -  179 

Bibliography  of  the  Nervous  System,      -  ib. 

CHAPTER  VIII. 

Tegumentarx  System,      -                        ....  182 


X  INDEX. 

Section  1.   General  observations,                -            -            -  ib- 

Section  2.   Of  the  Skin,                  -                         -            -  188 

Pathological  Anatomy,             -            -            -  198 

Sectiono.  Of  the  Mucous  Membranes,      -            -            -  205 

Pathological  Anatomy,             ...  213 

Section  4.  Of  the  appendages  of  the  Tegumentary  System,  217 

Article  1.   Of  the  Hairs,         ....  ib. 

Pathological  Anatomy,     ...  221 

Article  2.  Of  the  Nails,         -            -            -            -  222 

Pathological  Anatomy,                 -            -  225 

AtiticleS.   Of  the  Teeth,       ....  ib. 

Pathological  Anatomy,     -            -            -  230 

Bibliography  of  the  Tegumentary  System,  231 

CHAPTER  IX. 

Glandular  System,           ......  235 

Pathological  Anatomy,         ...  240 

Bibliography,            ....  241 

CHAPTER  X. 

Muscular  System,            ......  242 

Section  1.   General  observations,               -            -            -  ib. 

Pathological  Anatomy,             -            -            -  253 

Section  2.  Of  the  Exterior  Muscles,          -            -            -  255 

Section  3.  Of  the  Interior  Muscles,           -            -            -  259 

Bibliography  of  the  Muscular  System,              -  263 

APPENDIX,  containing  an  account  of  the  Accidental  Tissues,     -  264 

Article  1.  Of  Tubercles,       ....  266 

Article  2.  Of  Schirrus,          ....  268 

Article  3.  Of  Encephaloid  or  Cerebriform  Cancel',  269 

Article  4.  Of  Melanosis,        ....  270 

Bibliography  of  Pathological  Anatomy,  -  271 


INTRODUCTION. 


Life  is  the  phenomenon  which  results  from  the  actions 
of  an  assemblage  of  organs,  which  are  more  or  less  inti- 
mately connected  together  according  to  the  ultimate  func- 
tions which  they  are  destined  to  perform.  During  a  long  time 
the  study  of  the  organs  in  relation  to  their  form,  their  struc- 
ture and  physical  characters,  and  the  study  of  the  same  parts 
in  relation  to  their  functions,  were  always  combined,  and  were 
made  the  special  object  of  the  science  of  physiology.  But 
in  consequence  of  the  progress  of  our  knowledge  of  organi- 
zation, the  separation  of  these  two  kinds  of  study  has  become 
essentially  necessary.  Anatomy  is  the  science  which  treats 
of  the  conformation,  the  situation  and  structure  of  the  or- 
gans, while  physiology  regards  in  a  more  especial  manner, 
the  funptions  of  the  animal  economy. 

Anatomy  is  divided  into  two  branches;  into  special  and 
general  anatomy.  The  former  has  for  its  object  the  par- 
ticular study  of  each  individual  organ  enjoying  an  action 
peculiar  to  itself;  it  describes  the  physical  properties,  the 
form  and  relative  situation,  and  shows  the  mutual  arrange- 
ment of  the  elementary  tissues  which  contribute  to  its 
formation.  The  latter,  of  which  this  work  is  intended  to 
present  a  summary,  treats  of  the  elementary  tissues  and  or- 
ganic systems,  considered  in  a  general  point  of  view,  and 
abstractedly  of  the  organs  which  they  contribute  to  form. 

The  term  tissue  is  applied  to  every  species  of  the  ani- 
mal solids  having  peculiar  and  distinctive  characters.    The 
tissues  are  the  constituent  parts  of  our  organs,  or  in  other 
2 


INTRODUCTION. 


words,  their  elements.  Each  tissue,  regarded  as  a  whole, 
is  called  system,  in  whatever  part  of  the  body  it  is  found. 
The  human  body  is  composed  of  solids  and  fluids,  the 
latter  of  which,  form  by  far  the  most  considerable  share. 
Before  we  enter  upon  the  examination  of  the  organic  sys- 
tems, it  is  necessary  to  say  something  of  those  materials 
which  perform  a  general  and  important  character  in  the 
animal  economy — a  character,  which,  after  having  engag- 
ed for  ages  the  exclusive  attention  and  study  of  physicians, 
was  lost  sight  of  by  the  moderns,  who  uniformly  sought 
in  the  solids  the  seat  of  every  morbid  derangement. 

Of  the  Fluids. 

It  is  impossible  to  determine  with  any  degree  of  pre- 
cision, the  relative  quantity  of  the  solids  and  fluids:  some 
believe  that  the  latter  are  to  the  solids  as  six  to  one;  others 
that  their  relative  proportion  is  as  nine  to  one. 

The  fluids  are  contained  within  the  solids,  which  are 
more  or  less  penetrated,  according  to  the  kind  of  organ 
that  is  examined.  Their  fluidity  is  owing  more  to  the  vi- 
tal influence  than  to  the  quantity  of  caloric  which  they 
contain.  When  drawn  from  the  vessels  of  a  living  ani- 
mal, and  removed  from  the  heat  to  which  they  have  been 
exposed,  most  of  them  coagulate. 

The  animal  fluids  consist,  first,  of  the  fluids  which  are 
converted  into  blood;  secondly,  of  the  blood  itself,  which  is 
the  source  and  reservoir  of  all  the  other  humours;  and, 
thirdly,  of  the  fluids  which  are  derived  from  the  blood. 

Of  the  Fluids  which  are  converted  into  blood. 

The  fluids  which  are  converted  into  blood  are  the  lymph 
and  the  chyle.  The  lymph  is  the  milk-like  fluid  which 
results  from  the  changes  which  the  chymous  pulp  under- 
goes in  the  duodenum.  Examined  a  short  time  after  it  has 
been  absorbed  by  the  chyliferous  vessels  of  the  intestines, 
it  is  slightly  coagulable,  of  a  saltish  taste,  and  of  a  whitish 


INTRODUCTION.  3 

appearance.  In  the  glands  of  the  mesentery,  its  charac- 
ters are  sensibly  modified;  it  becomes  more  coagulable,  and 
presents  a  reddish  tint,  which,  upon  the  arrival  of  the  chyle 
in  the  thoracic  duct,  is  changed  to  a  beautiful  red  colour. 
Examined  with  the  microscope,  the  chyle  is  found  to  con- 
sist of  a  great  number  of  globules  and  corpuscles  which  are 
precisely  analogous  to  those  of  the  blood,  with  the  excep- 
tion of  their  colour,  which  is  much  fainter. 

Lymph  is  a  transparent,  viscid  and  albuminous  fluid, 
whose  quantity  is  much  smaller  than  is  commonly  sup- 
posed. It  is  contained  in  the  lymphatic  vessels,  and  is 
mixed  with  the  chyle  in  the  thoracic  duct. 

Of  the  Blood. 

The  blood  of  a  healthy  person,  is  a  fluid  of  abeautful  red 
colour,  contained  in  the  cavity  of  the  heart,  and  blood- 
vessels, and  varying  in  quantity  from  ten  to  twenty-five 
pounds.  When  flowing  from  its  vessels  in  the  living  anij 
mal,  it  is  an  unctuous  liquid  of  a  peculiar  odour  and  saline 
taste,  of  the  temperature  of  98°  of  Farenheit's  thermome- 
ter, and  of  the  specific  gravity  of  1050. 

The  microscopic  observations  of  Hewson,  Beclard,  Pre- 
vost  and  Dumas,  tend  to  prove  that  the  blood,  while  cir- 
culatingin  its  vessels,  is  nothing  else  than  the  serum,  hold- 
ing in  suspension  small,  regular,  and  insoluble  corpuscles. 
These  are  uniformly  composed  of  a  central,  colourless 
spheroid,  and  of  a  red,  semi-transparent  envelope. 

When  the  blood  has  ceased  to  be  under  the  vital  influ- 
ence, it  gradually  loses  its  heat,  disengages  a  considerable 
quantity  of  carbonic  acid  gas,  and  coagulates.  A  short  time 
after  coagulation,  the  clot  separates  into  two  elements;  the 
solid  part  is  called  the  crassamentum,  the  fluid  part,  the 
serum  of  the  blood.  When  the  coagulum  of  the  blood 
is  carefully  and  repeatedly  washed  in  a  small  stream  of 
water,  the  colouring  matter  is  gradually  disengaged,  and  a 
glutinous  and  fibrous  mass  remains,  which  has  been  termed 


4  INTRODUCTION. 

fibrin  or  coagulable  lymph.  This  substance  is  of  a  grayish 
colour,  of  a  firm  consistence,  and  has  all  the  properties  of 
the  muscular  fibre. 

-  The  serum  of  the  blood  is  of  a  greenish-yellow  colour, 
and  of  the  average  specific  gravity  of  1030.  It  is  alkaline, 
and  when  exposed  to  a  temparature  of  160°,  it  is  converted 
into  a  white  coherent  mass,  from  which  a  fluid,  termed  the 
serosity,  may  be  obtained  by  pressure.  According  to  the 
analysis  of  Dr.  Marcet,  the  serum  conists  of  the  following 
ingredients: — 


Water,         .... 

900.00 

Albumen,  .... 

.    86.80 

Muriate  of  potash  and  soda, 

.       6.60 

Muco  extractive  matter,     . 

4.00 

Sub-carbonate  of  soda, 

1.65 

Sulphate  of  potash, 

0.35 

Earthy  phosphates,    . 

0.60 

1000.00 

The  colouring  matter  of  the  blood  results  from  a  mix- 
ture of  the  disengaged  red  matter  and  the  serum.  It  is 
insoluble  in  water,  and  its  chemical  properties  show  that  it 
is  a  peculiar  animal  principle  united  with  a  per-oxide  of 
iron.* 

Besides  these,  the  blood  contains  an  unctuous  substance, 
and  a  halitus  which  is  seen  to  rise  from  the  surface  of 
blood  recently  drawn,  upon  the  same  principle  that  a  sensi- 
ble evaporation  takes  place  from  the  surface  of  other  li- 
quids whose  temperature  had  been  considerably  elevated. 

*  According  to  the  analyses  of  Berzelius,  the  colouring  matter  of  the 
blood,  after  being  incinerated,  affords  the  following  residue: — Oxide  of 
iron,  50.0;  sub-phosphate  of  iron,  7.5;  phosphate  of  lime  with  a  very 
small  proportion  of  magnesia,  6.0;  pure  lime,  20.0;  carbonic  acid  gas 
and  loss,  16.5.— 100.0.  (a)— S.  D.  G. 

(a)  Thomas's  System  of  Chemistry,  Vol.  IV. 


INTRODUCTION.  ^  5 

During  life  the  blood  is  constantly  subject  to  the  im- 
pulse of  the  heart,  which,  with  the  aid  of  other  causes,  pro- 
duces a  continual  circulation  in  its  cavities,  in  the  arteries 
and  the  veins.  In  the  course  which  it  traverses,  the  blood 
undergoes  continual  changes  in  its  composition  and  nature; 
— changes  which  have  for  their  ultimate  object  the  nour- 
ishment of  the  organs.  It  is  renewed  and  repaired  by  the 
chyle,  which  is  carried  to  it  by  the  thoracic  duct;  it  re- 
ceives the  refuse  of  all  the  absorbents,  as  well  as  the  mole- 
cules which  have  ceased  to  form  part  of  the  body;  it  is 
vivified  during  the  act  of  respiration,  by  which  it  loses  a 
considerable  quantity  of  serum  and  of  carbon,  absorbs  oxi- 
gen,  and  changes  from  a  dark  red  colour  to  a  beautiful  ver- 
milion: thus  restored,  it  becomes  the  source  of  all  the  se- 
cretions and  the  vital  principle  of  all  the  tissues  with  which 
it  is  incorporated. 

3.   Of  the  Fluids  ivhich  are  derived  from  the  blood. 

All  the  molecules  which  enter  into  the  composition  of 
our  organs,  or  are  thrown  oflf,  are  derived  from  the  blood, 
and  are  at  first  in  a  state  of  fluidity.  These  fluids  may  be 
divided  into  three  classes: — 

1.  Into  those  which  are  immediately  subservient  to  as- 
similation, to  the  growth,  and  reparation  of  our  organs,  or 
in  other  words,  into  those  fluids  which  are  especially  nu- 
tritive. 

2.  Into  those  which  are  deposited  into  certain  cavities, 
and  in  the  intervals  of  the  organs,  as  the  fat,  the  serum,  and 
synovia,  as  well  as  those  which  are  exhaled  on  the  surface 
of  the  body,  as  the  cutaneous  and  pulmonary  perspirations. 

3.  Into  those  which  are  the  production  of  a  glandular 
elaboration.  They  are,  the  mucus,  the  sebaceous  matter, 
the  lacrymal  fluid,  the  salivary  fluid,  the  bile,  the  pan- 
creatic fluid,  the  milk,  the  semen  and  urine. 


6  INTRODUCTION. 

Of  the  Tissues  and  Organic  Systems. 

It  is  difficult  to  determine  the  number  of  the  elementary 
tissues  of  the  body,  because  some  of  them  are  only  modi- 
fications of  each  other,  and  also  on  account  of  the  great  dis- 
crepancy in  the  opinions  of  authors  in^egard  to  this  sub- 
ject. Some  (Mascagni)  regapd  the  solids  as  being  com- 
posed entirely  of  vessels;  others  as  formed  of  cellular  tissue. 
Haller  has  admitted  the  existence  of  three  kinds  of  primary 
tissues  in  the  composition  of  our  organs,  viz.,  the  cellular, 
the  muscular,  and  the  nervous.  To  this,  M.  Chaussier  has 
added  the  albugineous  fibre  which  enters  mtp  the  composi- 
tion of  the  ligaments.  M.  Richerand  also  admits  these 
four  tissues,  besides  the  horny  substance  which  constitutes 
the  basis  of  the  epidermis,  the  nails,  and  the  hair.  Bichat 
divides  all  the  tissues  into  twenty-one,  three  of  which  are 
the  generators  of  the  rest.  These  tissues  are: — the  cellular, 
nervous  of  animal  life,  nervous  of  organic  life,  arterial, 
venous,  exhalent,  absorbent,  osseous,  medullary,  cartilagi- 
nous, fibrous,  fibro-cartilaginous,  muscular  of  animal  life, 
muscular  of  organic  life,  mucous,  serous,  synovial,  glandu- 
lar, dermoid,  epidermoid  and  pilous.  Beclard,  including 
several  of  the  preceding  systems  under  the  same  denomi- 
nation, after  Meckel,  has  described  successively  the  cellu- 
lar tissue,  the  serous  membranes,  the  tegumentary  mem- 
branes, the  vascular  system,  the  glands,  the  ligamentous 
tissue,  the  cartilages,  the  osseous  tissue,  and  the  muscular 
and  the  nervous  systems.  As  regards  ourselves,  in  admit- 
ting the  systems  established  by  M.  Meckel,*  we  have 

*  Meckel  recognises  ten  elementary  tissues: — the  mucous,  serous,  vas- 
cular, nervous,  osseous,  cartilaginous,  fibrous,  fib-o-cartilaginous,  muscu- 
lar, and  dermoid. 

M.  Adelon  divides  the  textures  or  systems  into  twelve  classes: — the 
cellular,  vascular,  nervous,  osseous,  cartilaginous,  fibrous,  muscular,  erec- 
tile, ?nucous,  serous,  corneous,  and  parenchimatous . 

Professor  Mayer  admits  only  seven  systems.— the  lamdkted  tissue,  the 


INTRODUCTION.  7 

adopted  an  arrangement  somewhat  different  from  those 
that  have  been  hitherto  followed:  we  have  endeavoured  to 
classify  the  tissues  in  a  manner  expressive  of  their  progres- 
sive complication.  Thus  we  have  placed  after  the  cellular 
and  vascular  tissues,  all  those,  which,  being  only  modifi- 
cations of  the  first,  present  nothing  in  their  organization  but 
vessels,  and  appear  to  be  destitute  of  nerves: — these  are 
the  serous,  the  fibrous,  the  cartilaginous,  and  osseous  sys- 
tems. Then  commences  a  second  series  at  the  head  of 
which  are  the  nervous  system,  and  those  which  are  com- 
posed of  the  tissues  that  are  formed  of  a  cellular  net-work 
of  vessels  and  nerves;  viz.,  the  tegumentary,  the  glandular 
and  muscular  tissues. 

Before  we  conclude,  it  is  necessary  to  observe  that  this 
work,  which  we  had  intended  to  write  together,  is  almost 
entirely  the  labour  of  M.  Hollard,  the  health  of  M.  Bayle 
having  permitted  him  to  take  but  a  feeble  part  in  it. 

ceUulo-fibrous  tissue,  the  fibrous  system,  the  cartilaginous  tissue,  the  osseous 
tissue,  the  muscular  fibre,  and  the  nervous  tissue.  S.  D.  G. 


MANUAL 

OF 

GENERAL   ANATOMY. 

CHAPTER  1. 

CELLULAR  SYSTEM, 

SECTION  1. 

Cellular  Tissue,  properly  so  called. 

Synonyma:  Cellular  substance,  body,  membrane,  org-an,  mucous  tissue, 
glutinous  tissue,  areolar  tissue,  reticular  tissue,  laminar  tissue,  fila- 
mentous tissue. 

Definition.  The  term  cellular  is  applied  to  a  soft  spungy 
tissue,  which  is  spread  throughout  the  whole  body,  con- 
nects the  various  organs  together,  surrounds  and  insinuates 
itself  between  them,  and  enters  into  their  substance  in  or- 
der to  contribute  to  their  structure. 

Division.  This  tissue  forms  a  complete  whole;  but  in 
consequence  of  the  different  relations,  and  of  the  more  or 
less  intimate  connexions  which  subsist  between  it  and  the 
various  organs  of  the  body,  it  is  necessary  to  distinguish  it 
into  common  and  special;  and  all  that  we  have  to  observe 
respecting  the  manner  in  which  the  cellular  tissue  is  ar- 
ranged in  the  animal  economy,  being  applicable  to  these 
two  divisions,  we  shall  commence  with  the  description  of 
the  first. 

1.    Common  cellular  tissue.     The  common  cellular  tis- 
sue regarded  as  a  whole,  presents  the  general  configura- 
3 


10  CELLULAR  TISSUE   PROPERLY    CALLED. 

tion  of  the  body,  forms  a  complete  subcutaneous  envelope, 
and  has  all  the  organs,  with  the  exception  of  the  teguments, 
embedded  in  its  mass.  Its  quantity  is  not  every  where  the 
same:  proceeding  from  the  exterior  to  the  interior  parts  of 
the  bod}T,  we  find  that  it  abounds  under  the  skin,  particu- 
larly in  the  face,  in  the  anterior  and  lateral  parts  of  the 
neck,  the  parietes  of  the  thorax  and  abdomen,  the  scrotum, 
in  the  vicinity  of  the  large  joints,  and  in  those  places  where 
extensive  flexion  is  performed,  especially  in  the  axillae 
and  groins;  between  the  lamina?  of  the  mediastinum,  around 
the  large  vessels,  in  the  inferior  part  of  the  cavity  of  the 
abdomen,  particularly  around  the  kidneys,  between  the 
folds  of  the  peritoneum,  but  still  more  around  the  pelvic 
viscera; — an  arrangement  favourable  to  the  changes  of 
volume  accompanying  the  exercise  of  their  functions. 
This  tissue,  on  the  other  hand,  is  thin  on  the  mesian  line 
of  the  body  (except  in  the  neck,)  under  the  teguments  of  the 
head,  in  the  cavity  of  the  cranium,  and  in  the  vertebral  ca- 
nal, especially  between  the  dura  mater  and  bony  case. 

The  common  cellular  tissue  which  is  spread  over  the  ex- 
terior parts  of  the  body,  communicates  with  that  of  the  in- 
terior by  all  the  interstices  which  are  left  between  the  dif- 
ferent organs,  but  in  a  still  more  remarkable  manner  by 
the  orifices  and  inter-organic  spaces  which  give  passage  to 
vessels  and  nerves.  This  kind  of  communication  takes 
place  in  the  holes  of  the  cranium  and  vertebral  column,  and 
in  the  cavity  of  the  thorax,  where  the  cellular  tissue  of  the 
neck  and  arms  enters  in  accompanying  the  vascular  trunks 
and  nerves  which  enter  and  pass  out  at  the  superior  part 
of  that  cavity.  From  the  thorax  it  passes  into  the  cavity 
of  the  abdomen  between  the  pillars  of  the  diaphragm  along 
with  the  oesophagus,  the  aorta  and  vena  cava;  and  at  the 
crural  arch  and  inguinal  ring,  it  communicates  with  the 
cellular  tissue  of  the  inferior  extremities. 

2.  Special  cellular  tissue.  Considered  in  its  more  di- 
rect relations  with  the  organs,  we  observe,  that  the  cellu- 


CELLULAR  TISSUE    PROPERLY    CALLED.  11 

Jar  tissue  surrounds  and  envelops  them  with  a  particular 
covering,  which  forms,  according  to  the  happy  expression 
of  Bordeu,  an  atmosphere  of  insulation,  that  enters  every 
where  into  their  intimate  structure. 

1.  The  cellular  tissue  which  covers  our  organs  is  form- 
ed by  a  condensation  of  the  common  cellular  tissue,  of 
which  it  is  a  continuation.  Its  thickness  varies  in  the  dif- 
ferent regions  of  the  body;  it  is  more  considerable  around 
the  parts  which  perform  extensive  motions,  and  those  which 
are  not  insulated  by  a  membranous  envelope,  as  the  thy- 
roid gland,  the  kidneys,  &c.  The  skin,  the  mucous  and 
serous  membranes,  the  vessels  and  excretory  ducts  are  lin- 
ed only  at  their  adherent  surfaces,  by  a  layer  of  cellular 
tissue. 

a.  Under  the  skin  this  layer  is  not  every  where  equally 
dense  and  compact:  it  is  most  so  in  the  palm  of  the  hand, 
the  sole  of  the  foot,  around  the  annular  ligaments,  and  on 
the  mesian  line  of  the  body;  on  the  other  hand,  its  laxity 
is  remarkable  in  the  eye-lids  and  scrotum. 

b.  The  submucous  layer  is  generally  more  dense  than 
the  preceding:  so  that  it  seldom  contains  any  collections  of 
serum:  this  character  is  indispensably  necessary,  in  order 
that  the  muscular  fibres  which  are  inserted  into  it  may 
have  a  point  of  attachment. 

c.  The  serous  membranes,  intended,  mostly,  to  facili- 
tate more  or  less  extensive  gliding  movements,  are  fur- 
nished, at  their  adherent  surface,  with  a  loose  cellualar  tis- 
sue, which  is  particularly  conspicuous  in  the  abdomen: 
notwithstanding,  some  parts  of  the  pericardium,  the  great- 
est part  of  the  synovial  and  arachnoid  membranes,  adhere 
intimately  to  their  respective  organs. 

d.  It  forms  layers  that  envelop  the  blood  vessels,  lympha- 
tics and  excretory  ducts:  those  around  the  arteries  are  ex- 
tremely compact,  condensed,  and  resisting,  in  order  to  pre- 
serve their  cylindrical  form  when  they  are  insulated;  those 
of  the  veins  and  lymphatics  are  less  thick  and  compact; 


12  CELLULAR  TISSUE    PROPERLY    CALLED. 

while  those  of  the  excretory  ducts  are  thicker  than  those 
of  the  veins  and  thinner  than  those  of  the  arteries. 

The  organs,  which  are  composed  of  a  substratum  of  seve- 
ral membranes,  present  a  more  or  less  compact  cellular  tis- 
sue between  them,  which  belongs  in  part  to  the  submu- 
cous and  subserous  layers  in  the  intestinal  canal  and  in  a 
portion  of  the  bladder,  and  which,  considered  in  relation 
to  their  tunics,  enjoys  the  character  of  the  exterior  cellu- 
lar tissue,  notwithstanding  it  must  be  regarded  as  interior, 
when  we  take  into  consideration  the  organs  with  which  it 
is  connected.  It  forms  in  fact  a  transition  between  the 
subdivision  of  which  we  have  just  spoken  and  the  follow- 
ing. 

2.  The  cellular  tissue,  after  having  covered  the  organs, 
enters  every  where  into  their  structure,  and  envelops  the 
most  minute  parts  of  their  substance.  Thus,  each  fasciculus, 
every  muscular  fibre  and  fibrilla,  the  glands  and  every  glan- 
dular particle,  are  surrounded  by  a  pouch  or  cellular  sheath. 
This  pouch  is  more  delicate  in  proportion  as  the  organic 
particle  which  it  surrounds  is  more  minute.  A  cellular  tis- 
sue, more  lax  than  that  which  forms  these  pouches,  separates 
them  from  each  other:  in  short,  the  interior  cellular  tissue  is 
destined  to  the  same  uses, in  relation  to  its  parts,  that  the  com- 
mon cellular  tissue  of  which  we  have  just  spoken,  performs 
for  the  organs.  We  perceive  but  little  cellular  tissue  in  the 
brain  and  spinal  marrow,  in  the  bones  and  ligaments;  and 
it  can  be  seen  in  the  cartilages  only  after  a  long  and  tedi- 
ous maceration. 

Structure.  What  is  the  interior  conformation  of  the 
cellular  tissue?  If  we  examine  a  portion  which  has  neither 
been  stretched  nor  distended  by  fluids,  it  will  present,  ei- 
ther the  aspect  of  a  homogeneous,  semi-transparent  sub- 
stance, or  an  appearance  of  a  lamellated  and  filamentous 
texture;  the  first  form  appertains  particularly  to  the  special 
cellular  tissue,  the  second  to  the  common  tissue:  moreover, 
if  we  separate  two  bodies  that  have  been  united  by  cellular 


CELLULAR  TISSUE  PROPERLY  CALLED.  13 

tissue,  we  shall  observe  that  the  latter  is  composed:  1st,  Of 
transparent  lamina,  especially  in  those  regions  where  it  is 
of  a  loose  texture,  as  in  the  eye-lids  and  scrotum;  and  2d, 
Of  filaments,  which  are  either  single,  or  interlaced  with 
these  laminae.  Both  are  soft  and  whitish,  and  may  be 
greatly  distended  before  they  break.  If  air  or  water  be 
Imtrodrrceo^into  this  tissue,  these  fluids  will  permeate  it 
with  the  greatest  facility  and  occupy  the  irregular  cells, 
which  are  formed  by  the  interlacement  of  the  laminse  and 
filaments,  to  which  we  have  just  alluded.  The  existence  of 
these  cells  can  be  rendered  evident  by  freezing  an  infiltrated 
limb;  numerous  little  icicles  will  be  formed,  and  show  by 
their  form  that  of  the  cells  which  they  occupied.  From 
these  facts  Haller,  Bichat,  Beclard  and  M.  de  Blainville, 
of  the  present  day,  as  well  as  most  of  the  English  and  Ita- 
lian anatomists,  have  concluded  that  the  cellular  tissue  has  a 
lamellated  and  filamentous  texture  from  which  resulted  the 
existence  of  irregular  permanent  cells,  varying  in  figure, 
and  communicating  with  each  other.  Bordeu,  notwith- 
standing, has  asserted  that  the  tissue,  now  under  consider- 
ation, was  merely  a  homogeneous  substance,  destitute  of 
form,  and  of  a  viscous,  gelatinous  nature.  Adopting  this 
method  of  observing,  Wolff,  and  more  recently  Rudolphi, 
Heusinger,  J.  F.  Meckel,  and  ethers,  have  maintained  that 
the  laminse,  filaments  and  cells  of  the  cellular  tissue  do  not 
naturally  exist,  but  that  they  are  produced  by  distention, 
and  that  similar  phenomena  may  be  produced  by  distend- 
ing a  mass  of  mucus  or  glue:  consequently  they  have  de- 
scribed the  cellular  tissue  under  the  name  of  the  mucous 
tissue.*  In  answer  to  these  assertions  we  may  observe: 
first,  that  the  texture  of  the  cellular  tissue  is  evident  in  a 
number  of  places,  without  previous  distention;!  secondly. 

*  May  we  call  this  tissue  an  amorphous  and  perfectly  homogeneous 
substance,  as  these  authors  conceive  it  to  be? 

f  Meckel  appears  to  acknov/ledge  this  fact,  by  saying1,  that  the  opinion 
opposed  to  his  is  at  least  too  common. 


14  CELLULAR  TISSUE  PROPERLY  CALLED. 

that  its  permeability  is  too  remarkable  to  belong  to  a  ho- 
mogeneous and  viscous  substance,*  and  that,  performing 
the  office  of  a  spongy  and  cellular  tissue,  it  ought,  thus  far, 
to  be  regarded  as  such. 

Our  ideas  of  the  nature  of  cellular  tissue  are  vague 
and  hypothetical.  According  to  Meckel,  it  consists  of  a 
coagulable  fluid  in  a  state  of  coagulation.  Ruisch  and 
Mascagni  assert,  that  it  is  composed  of  vessels;  Fontana,  of 
tortuous  cylinders.  Be  this  as  it  may  be,  it  is  certain  that 
it  is  supplied  with  a  great  number  of  capillary  vessels, 
which  it  furnishes  with  coats,  and  which  carry  red  blood 
only  when  they  are  in  a  state  of  inflammation 

Differences  according  to  age.  The  cellular  tissue,  the 
basis  of  all  the  others,  is  represented  in  the  first  periods  of 
gestation,  by  a  viscous  substance,  in  the  midst  of  which  the 
organs  are  developed — a  substance,  which  diminishes,  ac- 
quires consistence,  and  after  having  passed  from  a  state  of 
mucus  and  gelatine,  at  length  assumes  the  texture  which 
we  have  already  described.  Bichat  supposed  that  the  fila- 
ments and  layers  existed  in  the  first  period  of  the  embryon, 
and  could  not  be  perceived  on  account  of  their  tenuity  and 
the  quantity  of  the  fluid  which  filled  their  interstices.  As 
the  organs  are  developed,  the  mass  of  the  common  cellular 
tissue  gradually  diminishes;  notwithstanding,  it  continues 
to  be  predominant  for  many  years  after  birth.  The  same 
thing  takes  place  during  a  great  part  of  the  life  of  the  fe- 
male; hence,  that  rotundity  of  form  common  to  her  and  the 
infant.  In  the  latter,  the  cellular  tissue  is  more  delicate, 
its  serum  more  abundant,  and  its  vital  energy  more  con- 
spicuous than  at  any  subsequent  period  of  life.  In  the 
adult,  it  becomes  more  firm  and  condensed,  is  less  humid, 
forms  layers  of  a  more  compact  texture  and  renders  the 
subcutaneous  organs  more  prominent.  In  old  age,  it  is  dry, 

*  In  consequence  of  wounds  of  the  lungs,  air  sometimes  penetrates 
into  the  cellular  tissue  with  a  promptitude  and  facility  that  could  not  be 
explained  without  admitting  the  pre-existence  of  cells. 


CELLULAR  TISSUE  PROPERLY  CALLED.        15 

less  elastic,  and  somewhat  withered; — a  circumstance  to 
which  must  be  attributed  in  part,  the  wrinkles  under  the 
skin  of  old  people. 

Physical  and  chemical  properties.  The  cellular  tissue, 
almost  colourless  when  distended,  presents  a  grayish  white 
appearance  whenever  it  forms  a  thin  layer;  its  cohesion, 
which  is  in  direct  ratio  with  its  density,  forms  a  medium 
between  that  of  mucilage  and  the  fibrous  tissues.  It  is 
eminently  elastic. 

Exposed  to  putrefaction,  the  cellular  tissue  yields  to  it 
less  readily  than  many  other  animal  substances;  it  resists 
for  a  long  time  the  action  of  the  gastric  juices,  and  of  ebul- 
lition; and  months  are  scarcely  sufficient  for  its  maceration. 
It  is  composed  principally  of  gelatine,  with  a  small  quan- 
tity of  fibrin  and  earthy  salts. 

Vital  properties.  In  the  healthy  state,  the  sensibility 
of  this  tissue  is  very  obscure;  it  evidently  possesses  some 
degree  of  contractility  of  texture,  which  is  more  conspicu- 
ous in  youth  than  old  age. 

Functions.  The  common  cellular  tissue  serves  to  con- 
nect the  organs  together,  and  by  its  pliancy  and  elasticity, 
to  facilitate  their  motions.  It  serves,  more  immediately, 
to  form  around  them  a  kind  of  atmosphere,  which  contri- 
butes to  protect  them  from  the  diseases  of  the  neighbouring 
parts;  and,  in  furnishing  an  envelope  for  their  most  minute 
corpuscles,  to  determine  their  extent  and  configuration. 
This  tissue  is  the  seat  of  a  serous  exhalation,*  principally 
composed  of  albumen,  which  moistens  it  continually,  and 
serves  to  facilitate  the  motions  of  the  contiguous  parts.  It 
is  small  in  quantity,  and  when  the  tissue  which  it  lubri- 
cates is  laid  bare  in  a  living  animal,  it  appears  under  the 
form  of  vapour:  it  is  continually  furnished  by  the  exhalents 
and  taken  up  by  the  absorbents.     We  may  observe,  that  its 

*  Many  anatomists  suppose  that  this  secretion  is  produced  by  an  ela- 
borating- process  of  the  cellular  tissue. 


16  CELLULAR  TISSUE   TKOPERLY  CALLED. 

quantity  is  in  an  inverse  ratio  to  that  of  the  fat  in  the  dif- 
ferent regions.* 

Pathological  Jlnatomy. 

The  cellular  tissue  is  the  basis  of  many  adventitious  pro- 
ductions, as  polypi,  fungi,  cicatrices,  &c.  &c.  which  prove 
its  great  plastic  energy. 

When  a  re-union  can  not  he  immediately  effected,  after 
a  solution  of  continuity,  the  denuded  surface  puts  on  an  in- 
flamed appearance,  and  soon  after  becomes  covered  with 
red  granules,  improperly  called  fleshy  granulations,  since 
they  result  from  a  development  of  the  inflamed  cellular 
tissue,  and  not,  as  was  asserted  by  Galen,  from  a  repro- 
duction of  flesh.  As  these  granulations  grow,  they  secrete 
purulent  matter,  become  uneven  at  their  surface,  and  con- 
tract; while  this  is  taking  place,  the  secreted  matter  be- 
comes thicker,  and  is  at  length  organized  under  the  form 
of  a  thin  pellicle,  which  is  continued  with  the  neighbouring 
epidermis:  under  this,  the  depressed  granulations  are  con- 
verted into  a  wrinkled  tissue,  which  is  analogous  to  the 
chorion  of  the  skin,  and  which  gradually  loses  its  reddish 
tint,  and  becomes  whiter  than  the  original  skin.  This 
forms  what  is  called  a  cicatrix.  These  phenomena  take 
place  from  the  circumference  towards  the  centre  of  the 
wound,  whose  edges  approximate,  from  this  last  point,  in 
consequence  of  the  contractions  of  the  granulations.  From 
this  it  results  that  the  cicatrices  occupy  less  space  than  the 
original  wound.  After  the  immediate  re-union  of  a  solu- 
tion of  continuity,  there  are  neither  granulations  nor  pus; 
the  cicatrix  being  formed  by  an  effusion  of  adhesive  matter 
upon  the  surface  of  the  wound,  which  becomes  at  first  more 

*  The  fatty  fluid  placed  hitherto  upon  the  same  line  as  the  serosity  in 
the  history  of  the  cellular  tissue,  appears  to  be  deposited  in  a  particular 
tissue  which  has  been  described  separately,  as  a  modification  of  the  cel- 
lular tissue:  as  this  distinction  appears  to  be  well  founded,  we  shall  de- 
scribe the  adipose  or  fatty  tissue  under  a  distinct  section. 


CELLULAR  TISSUE  PROPERLY  CALLED.  17 

dense  than  the  cellular  tissue,  but  is  finally  confounded 
with  it. 

The  cellular  tissue  is  frequently  distended  by  collections 
of  the  serum,  which  lubricates  it.  When  this  affection  is 
local,  it  is  termed  anasarca,  and  oedema,  when  it  extends 
throughout  the  whole  system.  It  is  most  frequently  con- 
nected with  chronic  diseases  of  one  or  more  of  the  princi- 
pal viscera,  or  with  an  obstruction  of  the  circulation:  the 
most  dependent  parts  of  the  body  are  the  ordinary  seat  of 
oedema.  When  serum  is  extravasated  into  the  cells  of  the 
cellular  tissue,  it  leaves  the  part  where  it  is  found  as  soon 
as  their  position  is  rendered  less  dependent;  another  proof 
of  the  great  permeability  of  this  tissue  and  of  the  pre-exist- 
ence  of  its  cells.  Air  sometimes  penetrates  into  this  tissue, 
in  consequence  of  wounds  of  the  thorax,  &c;  gas  also  is 
disengaged  in  certain  cases;  this  kind  of  infiltration  is  called 
emphysema.  The  cellular  tissue  is  frequently  the  seat  of 
phlegmonous  inflammation,  which  may  be  dispersed  by 
resolution:  when  acute,  it  often  terminates  in  suppuration, 
that  is,  by  the  secretion  of  a  white,  inodorous,  cream-like 
fluid,  (pus)  which,  being  at  first  disseminated  through  the 
cells  in  which  it  is  formed,  collects  into  an  abscess,  .and  has 
a  tendency  to  travel  towards  the  surface;  which  is  readily 
effected  when  the  inflammation  has  some  degree  of  inten- 
sity and  the  situation  of  the  purulent  abscess  is  not  obstruct- 
ed: under  these  circumstances  portions  of  cellular  tissue  are 
often  discharged  with  the  pus.  If  the  disease  is  somewhat 
slow  in  its  progress,  the  parietes  of  the  abscess  become 
lined  by  a  membrane,  resulting  from  the  condensation  of  the 
cellular  tissue,  and  which  has  some  analogy  to  the  mucous 
membranes.  When  the  pus  is  evacuated,  these  parietes 
approximate  and  the  cavity  of  the  abscess  is  obliterated;  or 
if  the  matter  continues  to  discharge,  the  course  which  it 
takes  to  arrive  at  the  external  surface,  is  also  lined  by  a 
mucous  membrane,  and  is  thus  converted  into  a  fistula.  In 
some  instances,  the  abscesses  are  intersected  by  bands  and 


18  CELLULAR  TISSUE  PROPERLY  CALLED. 

partitions,  which  are  nothing  more  than  the  remains  of  the 
cellular  tissue  which  occupied  their  cavity.  The  gangren- 
ous eschars,  which  often  result  from  acute  phlegmonous  in- 
flammation, are  soft  and  grayish,  and  are  called  ventriculi 
furuncu/orum.  Those  which  are  formed  in  some  phleg- 
monous tumours,  as  furunculus  and  anthrax,  are  attributed 
to  a  kind  of  strangulation  of  the  inflamed  cellular  tissue. 
Inflammation,  after  it  has  passed  into  the  chronic  state, 
often  deposits  into  the  cells  of  the  cellular  tissue,  a  kind  of 
concrete  matter,  which  gives  rise  to  the  alteration  called 
white  induration:  this  constitutes  the  granulations  which 
are  often  exhibited  in  the  subserous  and  submucous  cellular 
layers.  The  elephantiasis  of  Barbadoes  consists  in  a  morbid 
derangement  of  this  kind. 

The  induration  of  newly  formed  cellular  tissue,  which 
M.  Chaussier  has  called  scleremas,  is  a  disease  almost  ex- 
clusively confined  to  infants,  and  is  characterized  by  a  con- 
siderable degree  of  firmness  and  consistency  of  this  tissue, 
especially  of  the  subcutaneous:  incisions  made  into  it  pro- 
duce a  discharge  of  a  yellowish  fluid,  which,  according  to 
Meckel,  consists  of  a  mixture  of  fat  and  serum.  By  Andry 
this  disease  is  attributed  to  a  suppression  of  the  cutaneous 
perspiration;  by  others,  to  an  effect  of  syphilitic  virus. 
According  to  the  researches  of  M.  Breschet,  it  is  attended 
with  an  opening  of  the  foramen  of  Botal,  and  consequently 
by  a  very  evident  imperfection  in  the  function  of  respira- 
tion. 

When  foreign  bodies  are  introduced  into  the  cellular 
system,  they  cause  inflammation  in  the  contiguous  parts, 
and  are  most  frequently  discharged  by  suppuration;  though 
sometimes  they  penetrate  to  a  considerable  distance:  intro- 
duced into  the  alimentary  canal,  they  often  pierce  its  coats, 
and  are  conveyed  through  the  different  regions  of  the  body, 
without  occasioning  any  serious  mischief.*  The  cellular  tis- 

*  A  case  of  this  kind  occurred  in  a  woman  who  suffered  from  mania, 
in  consequence  of  swallowing  needles.     She  died  several  years  after  at 


CELLULAR  TISSUE  TROPERLY  CALLED.  19 

sue  is  sometimes  condensed  around  them  and  forms  a  mem- 
branous covering  or  cyst  (v.  Serous  System.)  The  blood, 
the  product  of  the  secretions  and  the  excrements  are  some- 
times extravasated  into  this  tissue  and  act  as  foreign  bodies: 
the  blood,  at  first  diffused  through  the  cells  of  the  cellular 
tissue,  constitutes  what  is  called  ecchymosis,  and  is  often 
brought  to  a  focus  before  it  can  be  absorbed:  hence,  it  is 
converted  into  a  coagulum,  which,  being  enveloped  in  a 
serous  cyst,  is  soon  after  more  or  less  readily  absorbed. 
When  the  pecrementitial  secretions  are  extravasated,  they 
readily  enter  the  circulation;  and  their  presence  in  the  cel- 
lular tissue  often  brings  on  the  most  fatal  inflammations. 

The  cellular  tissue  is  sometimes  the  seat  of  organized 
beings,  such  as  hydatids,  &c;  the  filaria  dracunculus  of 
Bremser,  and  the  furia  infernalis  enter  it  by  piercing  the 
skin. 

Bibliography. 

Th.  de  Borden.  Recherches  sur  le  tissue  muqueux  ou  or- 
gane  cellulaire,  etc.  Paris,  1767 — 1791,  et  dans  les 
(Euvres  completes  publiees  par  le  chevalier  Richerand. 
Paris,  1818. 

Haller.  Elem.  phys.  corp.  hum.,  1. 1,  p.  9.  Lausanne,  17S7. 

X.  Bichat.  Anatomie  generale,  tome  I,  page  100.  Ed. 
de  Beclard.  Paris,  1821. 

Br.  Hay  ward's  Trans,  of  the  same,  vol.  I,  page  87.  Bos- 
ton, 1822. 

P.  Ji.  Beclard.  Elemens  d'anatomie  generale,  1  vol.  in  8. 
Paris,  1S23,  p.  133. 

J.  Fr.  Meckel.  Handbuch  der  menschlichen  anatomie, 
c'est-a-dire,  Manual  d'anatomie  humaine,  traduit  en 
frangais  sous  le  titre  de  Manuel  d'anatomie  generale,  de- 
scriptive et  pathologique;  par  MM.  Jourdan  et  Breschet. 
Paris,  1825,  tome  I,  page  103. 

the  Hospital  of  St.  Louis,  and  upon  post  mortem  examination,  several 
hundred  of  these  small  instruments  were  found  in  the  cellular  tissue  of 
the  different  parts  of  the  body. 


20  ADIPOSE  TISSUE. 

SECTION  2. 

Adipose  Tissue. 

Synononyma:  Cellulo-fatty  tissue,  fatty  membrane,  web  (toile,-)  adipose 

tunic. 

The  existence  of  the  vesicular  tissue  into  which  the  fat 
is  deposited,  has  not  been  acknowledged  by  all  anatomists. 
Malpighi,Morgagni,  and  particularly  Mr.  W.  Hunter,  and 
more  recently,  Proschaska,  Mascagni,  MM.  Chaussier, 
and  Beclard,  have  described  this  tissue  as  distinct  from 
the  preceding;  but  Bichat,  adopting  the  ideas  of  Haller,  as- 
serted that  the  fat  was  exhaled  and  deposited  like  the  serum 
into  the  areolae  of  the  cellular  tissue.  In  our  day,  J.  F. 
Meckel  has  described  the  fatty  fluid  as  contained  in  small 
rounded,  irregular  vesicles,  formed  evidently  by  a  kind  of 
gluten,  which,  according  to  him,  constitutes  the  cellular 
tissue.  The  facts  upon  which  the  distinction  of  this  and 
the  adipose  tissue  rest,  re-established  lately  again  by  Be- 
clard, have  appeared  sufficiently  conclusive  to  justify  us 
in  describing  this  tissue  under  a  distinct  section., 

Definition.  The  adipose  tissue  consists  of  small,  micro- 
scopic vesicles  joined  together  in  more  or  less  considera- 
ble masses  and  filled  with  fat. 

Situation.  The  adipose  tissue  abounds  exteriorly  un- 
der the  skin  of  the  face,  the  neck,  the  anterior  parts  of  the 
thorax,  the  abdomen,  the  nates,  the  palms  of  the  hand  and 
the  soles  of  the  feet,  and  in  the  great  interstices  between 
the  muscles.  It  is  to  the  accumulation  of  a  great  quantity 
of  this  tissue  that  is  to  be  attributed  the  enormous  devel- 
opment of  the  nates  of  the  Hottentot  women,  of  the  tail  of 
the  Barbary  sheep,  and  the  prominences  on  the  backs  of 
some  animals,  that,  for  instance,  of  the  camel.  Interiorly, 
the  adipose  tissue  occurs  chiefly  around  the  great  vessels, 
on  the  surface  of  the  heart,  around  the  kidneys,  between 


ADIPOSE  TISSUE.  21 

thefolds  of  the  mesentery  and  the  omentum.  It  exists  more- 
over under  the  denomination  of  the  medullary  substance, 
in  the  bones  where  it  occupies  the  cells  of  the  spongy  and 
reticular  substance,  the  microscopic  interstices  of  the  compact 
substance  and  the  medullary  canal  of  the  long  bones:  here  the 
adipose  vesicles  are  deposited  into  the  cells  of  a  cellulo-vascu- 
lar  membrane,  of  which  we  shall  speak  more  particularly  in 
the  history  of  the  osseous  system.  The  interior  of  the  cra- 
nium, the  globe  of  the  eye,  the  eye-lids,  the  penis  and  the 
scrotum,  the  submucous  cellular  tissue,  the  lungs,  &c.  are 
in  general  destitute  of  fat.*  In  persons  of  ordinary  plump- 
ness, the  fat  is  generally  wanting  in  those  organs  where 
its  presence  would  interfere  with  the  exercise  of  their 
functions. 

Differences  of  situation  and  quantity,  according  to 
age  and  sex. — It  is  not  until  about  the  fifth  month  after 
conception,  that  the  foetus  presents  some  insulated  adipose 
vesicles,  and  then  only  under  the  skin.  After  birth,  it 
becomes  more  abundant,  is  seen  in  the  more  deep  seated 
parts,  and  finally  in  the  visceral  cavities.  Its  quantity  is 
much  greater  in  adult  age,  than  in  the  subsequent  periods 
of  life,  and  in  woman  than  in  man.  In  old  age,  it  occurs 
almost  exclusively  around  the  viscera  of  the  thorax  and  the 
abdomen. 

Form.  The  adipose  tissue  is  sometimes  seen  under  the 
form  of  considerable  laminae,  as  under  the  skin;  sometimes, 
under  that  of  pelatons,  as  in  the  orbits;  and  at  others,  un- 
der that  of  bands,  as  in  the  epiploons,  &c. 

Structure.  In  examining  the  texture  of  a  portion  of  adi- 

*  "If  the  cellular  membrane,"  says  Dr.  W.  Hunter,  "had  been  adi- 
pose in  the  eye-lids,  fat  people  must  have  been  blind;  if  in  the  substance 
of  the  lungs,  they  must  have  been  suffocated.  Had  it  been  adipose 
within  the  skull,  fat  people  would  have  been  as  liable  to  apoplexies  as 
to  ruptures;  and  if  it  had  not  been  reticular  in  the  penis,  fat  men  would 
have  been  much  incommoded."  Med.  Obs.  and  Inq.  v.  ii.  p.  31,  Lon- 
don, 1762.— S.  D.  G. 


22  ADIPOSE  TISSUE. 

pose  tissue,  it  will  appear  at  first  sight  to  be  composed  of 
small,  oblong  masses  which  result  from  an  assemblage  of 
military  granules,  formed  by  the  agglomeration  of  a  multi- 
tude of  small  round  and  transparent  vesicles,  which  are 
somewhat  compressed  and  visible  only  by  the  aid  of  the 
microscope.  The  coats  of  these  vesicles,  which  probably 
result  from  a  modification  of  the  cellular  tissue,  are  indis- 
tinct, yet  their  existence  can  noibe  doubted  for  the  follow- 
ing reasons;  1st,  When  a  portion  of  adipose  tissue  is  ex- 
posed to  a  temperature  capable  of  melting  the  fat  which  it 
contains,  it  does  not  run  out,  which  would  take  place  were 
the  fat  not  confined  within  the  cells  of  the  cellular  tissue. 
2d,  Although  fluid  during  life  it  never  gravitates,  however 
abundant  it  may  be,  toward  the  more  dependant  organs, 
and  3d,  it  is  not  like  the  cellular  tissue,  spread  throughout 
the  whole  body,  a  fact,  which  would  at  least  indicate  some 
difference  of  organization.  The  adipose  vesicles  are  con- 
nected together  by  very  fine  cellular  tissue,  and  are  sup- 
plied with  blood  vessels  that  may  be  readily  injected.- 
These  ramify  at  first  between  the  small  oblong  masses, 
forming  there  a  kind  of  net-work  which  sends  to  each  grain 
a  pedicle  composed  of  an  artery  and  a  vein,  whose  ramifi- 
cations are  distributed, like  so  many  smaller  pedicles,  to  each 
vesicle  in  which  they  appear  to  terminate.  There  is  but  little 
known  with  respect  to  the  lymphatic  vessels  of  the  adi- 
pose tissue,  and  we  are  yet  entirely  ignorant  whether  it  re- 
ceives any  nerves. 

Physical  and  chemical  properties.  The  extreme  tenui- 
ty of  the  adipose  vesicles  is  the  reason  that  we  know  no- 
thing of  its  physical  and  chemical  properties,  except  those 
which  result  from  the  presence  of  the  fat  contained  in  the 
adipose  tissue. 

Vital  properties.  In  the  healthy  state,  the  adipose  tis- 
sue, is  entirely  destitute  of  sensibilit}1",  and  can  not  be  dis- 
tinguished, even  when  in  a  state  of  inflammation,  from  that 


ADIPOSE    TISSUE.  23 

of  the  surrounding  cellular  tissue.  Its  contractility  is  very- 
obscure,  but  it  probably  participates  in  that  of  the  preced- 
ing tissue. 

Functions.  The  adipose  vesicles  serve  as  a  reservoir 
for  the  fat,  which  is  fluid  during  life,  and  varies  in  colour, 
consistence  and  odour  in  the  different  kinds  of  animals. 
Human  fat  is  an  inodorous  substance,  of  a  yellowish  co- 
lour, ofa  faint  sweetish  taste,  specifically  lighter  than  wa- 
ter, and  fusible  at  a  temperature  of  15°  cent.*  It  is  insolu- 
ble in  water,  and  less  soluble  in  cold  than  boiling  alcohol. 
At  an  elevated  temperature  it  is  decomposed,  and  affords 
hydrogen,  oxigen  and  carbon  in  various  degrees  of  combi- 
nation. Its  combination  with  the  oxigen  of  the  air  gives 
rise  to  the  sebacic  acid.  By  distillation,  it  yields  Celtic  acid 
and  a  considerable  quantity  of  defiant  gas;  and  by  treating 
it  with  the  alkalies  we  obtain  the  margaritic  and  oleic  acids 
and  the  sweet  principle,  (Chevreul.)  These  last  products 
do  not  exist  naturally,  but  are  the  results  of  new  combina- 
tions. The  experiments  of  M.  Chevreul  have  shown,  that 
the  fat  contains  two  proximate  principles,  to  which  he  has 
given  the  names  of  elaine  and  stearine;  the  former,  solu- 
ble in  alcohol,  fluid  at  7°  cent,  the  latter  less  soluble  in  al- 
cohol and  fluid  at  a  little  below  3S°  cent.  The  degree  of 
fusibility  of  every  kind  of  fat  is  in  proportion  to  the  rela- 
tive quantity  in  which  these  two  principles  are  combined. 

Various  are  the  hypotheses  that  have  been  advanced  re- 
specting the  manner  in  which  the  fat  is  secreted,  and  the 
organic  agents  upon  which  it  depends.  Malpighi  believed 
for  a  short  time,  that  the  vessels  of  the  adipose  tissue  were 
accompanied  by  a  small  secretory  apparatus;  but  this  great 
anatomist  soon  abandoned  an  idea  which  was  utterly  desti- 
tute of  foundation,  and  which  has  since  given  way  to  others. 
Riegel  asserted  that  the  glands,  and  particularly  the  capsu- 
Ise  renales,  were  the  secretory  organs  of  the  fat.  Haller 
supposed  that  it  circulated  with  the  blood;  that  it  floated 
*  The  harder  varieties  of  fat  fuse  at  about  120°  Fah.— S.  D.  G, 


24  ADIPOSE    TISSUE. 

upon  its  surface  on  account  of  its  specific  levity,  and  escap- 
ed through  the  coats  of  the  vessels;  but  the  most  common- 
ly received  opinion  of  the  present  day,  is,  that  the  fat  is  ex- 
haled from  the  parietes  of  the  adipose  vesicles.  This  ex- 
halation is  sometimes  remarkably  abundant,  especially  af- 
ter protracted  abstinence;  it  is  also  favoured  by  sedentary 
habits,  a  farinaceous  diet  and  castration.  It  is  here,  as 
every  where  else,  continually  counterbalanced  by  absorp- 
tion, which  frequently  exceeds  it,  particularly  in  some  of 
the  chronic  diseases  of  the  principal  viscera,  in  cases  of  pro- 
tracted or  profuse  suppuration,  diarrhoea,  and  some  other  af- 
fections. 

The  fat  appears  to  be  useful  in  the  animal  economy,  prin- 
cipally by  protecting  certain  parts  from  the  inconveniencies 
of  habitual  pressure  to  which  some  of  them  are  exposed; 
such  is  its  use  in  the  soles  of  the  feet,  the  nates  and  some  other 
parts.  As  a  bad  conductor  of  caloric,  it  contributes  in  some 
degree  to  the  preservation  of  that  of  the  body;  but  its  most 
important  office  appears  to  be  nutrition,  and  it  may  be  re- 
garded, if  we  may  be  allowed  the  expression,  as  aliment 
in  reserve.  Examples  of  this  kind  are  furnished  us  in  hy- 
bernating  animals.  The  fat  in  the  bones  appears  to  answer 
no  other  purpose  than  that  of  the  other  organs.  It  was 
falsely  asserted  by  Haller  that  it  renders  the  bones  less 
brittle,  that  it  was  subservient  to  their  consolidation  after 
fractures,  to  their  nutrition,  &c.  &c 

Pathological  Jlnatomy. 

Obesity,  or  polysarcia,  as  it  is  technically  called,  results 
from  the  excessive  development  of  the  adipose  tissue,  and 
may  be  regarded  as  a  morbid  derangement  which  impedes 
the  functions  of  the  other  organs.  When  this  extraordina- 
ry growth  is  local  it  is  termed  lipoma.  It  is  often  sur- 
rounded by  a  kind  of  cyst,  and  generally  presents  one  or 
more  peduncles.  Tumours  of  this  description  have  been 
seen  that  have  weighed  from  thirty  to  forty  pounds.  They 


ADIPOSE    TISSUE.  2o 

are  all  of  an  irregular  spheroidal  figure,  and  are  most  com- 
monly seated  beneath  the  skin;  sometimes,  however,  they 
are  found  in  the  cavities  of  the  thorax  and  the  abdomen, 
particularly  in  the  omentum:  when  they  pass  out  through 
the  inguinal  ring,  &c.  they  are  called  fatty  hernias.  In- 
flammation of  lipomatous  tumours  and  of  the  cellular  tis- 
sue in  general,  frequently  terminates  in  gangrene:  this 
morbid  state,  also, may  bringon  schirrous  and  carcinomatous 
affections.  The  adipose  tissue  is  often  developed  in  the 
ovaries,  in  the  submucous  cellular  tissue,  and  in  other 
parts  where  it  is  seldom  found  in  the  healthy  state.  The 
muscles  and  some  other  organs  are  subject  to  fatty  produc- 
tions, which  according  to  Beclard  belong  only  to  the  for- 
mer. Of  these  we  shall  speak  in  the  history  of  those  or- 
gans in  which  they  are  developed. — Traumatic  inflamma- 
tion of  the  adipose  tissue  produces  an  evacuation  of  the  vesi- 
cles and  an  effusion  of  the  fat  upon  the  surface  of  the 
wound,  which  is  soon  covered  with  cellulo-vascular  granu- 
lations, and  is  cicatrized  in  the  same  manner  as  we  point- 
ed out  in  the  preceding  section. 

In  the  infiltrations  of  the  cellular  tissue,  the  serum  is  ex- 
travasated  between  the  granules  and  the  adipose  vesicles, 
so  as  to  separate  them  from  each  other,  and  to  render 
them  very  distinct. 

Bibliography. 

Malpighi.     De  omento,  pinguedine,  etc.,  m  Epist.   anat. 

London,  1686,  p.  33. 
W.  Hunter.  Remarks  on  the  cellular  membrane,  etc.,  in 

Medic.  Obs.  and  Inq.  vol.  2.  p.  26.  London,  1762. 
Biclard.  Op.  Cit.  p.  156. 
ChevrenZ,  dans  les  Annales  de  Chimie,  tome  xciv,  et  les 

Annales  de  chimie  et  de  physique,  tomes  n — vn. 
J.  e/2.  Sayssi.  Secherces  experimentales  anatomiques,  chi- 

miques,  etc.,  sur  la  physiologie  des  animaux  mammife- 

reshibernas.  Paris,  1808. 


26  VASCULAR    SYSTEM. 


CHAPTER  II. 

- 

VASCULAR  SYSTEM. 


SECTION  1. 

General  Observations. 

Definition. — The  vascular  system  is  composed  of  an  as- 
semblage of  membranous  tubes  or  vessels,  which  are  uni- 
ted together  so  as  to  present  an  arborescent  arrangement,  and 
are  traversed  by  the  fluids  which  are  subservient  to  nutri- 
tion and  secretion. 

Division. — This  system  presents  three  orders  of  vessels: 
two  convey  the  blood,  and  are  called  arteries  and  veins; 
the  third  comprehends  the  lymphatic  vessels,  which  carry 
to  them  the  lymph  and  chyle,  white  fluids,  the  first  of 
which  is  derived  from  all  the  organs,  and  the  second,  the 
product  of  digestion,  is  absorbed  on  the  internal  surface  of 
the  intestines. 

Considered  in  their  relations  with  the  heart  and  the  nature 
of  the  blood  which  traverses  them,  the  arteries  and  veins 
have  been  distinguished  into  those  of  the  pulmonary  and 
those  of  the  general  system;  but  Bichat,  struck  with  the 
analogy  of  their  functions  rather  than  their  anatomical  cha- 
racters, united  the  vessels  which  correspond  to  the  same 
lateral  halves  of  the  heart,  and  obtained  the  most  beautiful 
results  from  this  division  of  the  sanguineous  system  into  the 
circulation  of  red  and  that  of  black  blood. 

General  conformation. — The  three  divisions  of  the  vas- 
cular system  form  an  uninterrupted  whole,  which  is  called 


VASCULAR   SYSTEM.  27 

the  circulatory  apparatus,  because  its  arrangement  is 
such,  that  the  fluids  which  traverse  it,  return  to  the  cen- 
tre where  they  began  their  circuit:  let  us  give  a  general 
idea  of  it. 

An  artery,  called  the  aorta,  arises  from  the  left  ventri- 
cle of  the  heart,and  carries,  by  its  numerous  ramifications, 
the  red  arterial  blood  to  every  part  of  the  body;  hence, 
arise  a  multitude  of  small  veins  which  are  continuous  with 
the  minute  extremities  of  the  arteries,  and  which,  uniting 
successively,  terminate,  after  having  received  the  lympha- 
tic vessels,  by  the  two  venae  cavse  and  coronary  vein,  which 
pour  the  dark  venous  blood  into  the  right  auricle  of  the 
heart.  From  the  right  ventricle  of  the  heart  originates  the 
pulmonary  artery,  whose  divisions,  multiplied  ad  infini- 
tum, distribute  this  black  blood  through  the  lungs,  where, 
by  the  act  of  inspiration,  it  is  converted  into  a  beautiful  red 
colour,  as  it  passes  from  the  minute  arterial  extremities  into 
those  of  the  venous:  these  last  form,  by  their  successive 
junctions,  small  ramifications,  then  branches,  and  termi- 
nates by  the  four  pulmonary  veins,  in  the  left  auricle  of 
the  heart. 

We  have  already  said,  that  the  heart  is  the  point  of  uni- 
on of  the  great  vascular  trunks:  in  proportion  as  these  re- 
cede from  their  origin,  they  divide  into  branches,  these 
branches  into  smaller  ones,  and  these  progressively  into 
more  and  more  minute  ramifications.  All  the  vessels  are 
of  a  cylindrical  form,  and  preserve  a  uniform  diameter  from 
the  place  of  their  origin  to  that  in  which  they  ramify.  This, 
for  instance,  is  the  case  with  the  spermatic  artery,  which 
traverses  a  long  course  without  changing  its  dimensions.  If 
any  of  the  smaller  branches  be  less  than  the  branch  from 
which  they  arise,  their  united  caliber  will  be  greater  than 
that  of  the  original  branch;  so  that  the  vascular  system  re- 
ally increases  as  it  becomes  more  remote  from  the  heart: 
it  is  in  this  way  that  anatomists,  by  reflecting  on  the  divi- 
sions of  this  system,  have  compared  it  to  a  cone,  the  apex 


28  VASCULAR    SYSTEM. 

of  which  is  formed  by  the  heart,  and  the  base,  by  the  ex- 
tremities of  the  smaller  vessels. 

The  s}rmmetry  of  the  vascular  system  is  by  no  means  so 
•  uniform  as  that  of  the  nervous  system.  The  heart  and 
great  trunks  are  not  placed  exactly  on  the  median  line,  and 
the  vessels  that  correspond  are  not  all  given  off  in  the 
same  manner;  thus,  the  arteria  innominata  gives  origin  on 
the  right  side,  to  the  subclavian  and  primitive  carotid, 
which,  on  the  left  side,  arise  separately  from  the  aorta;  in 
general,  however,  the  origin  of  the  trunks  is  pretty  uni- 
form; while  that  of  the  branches  is  so  variable  that  hardly 
any  two  subjects  present  the  same  arrangement. 

Differences  of  vascularity  in  the  different  organs. — 
The  organs  do  not  all  possess  the  same  degree  of  vasculari- 
ty; those  which  are  the  most  plentifully  supplied  with 
blood-vessels  are:  first,  the  lungs,  the tegumentary  system, 
the  pia  mater  and  choroid  membrane,  the  glands,  the  folli- 
cles, the  cortical  substance  of  the  brain,  the  nervous  gan- 
glia, the  muscles  and  glandiform  bodies;  secondly,  those 
which  are  most  abundantly  supplied  with  lymphatic  ves- 
sels are:  the  lymphatic  ganglia,  the  serous  membranes,  the 
cellular  tissue  and  glandiform  bodies. — No  vessels  have 
hitherto  been  demonstrated  in  the  cartilages  and  appenda- 
ges of  the  skin.  The  azygos  organs,  which  are  divided  into 
two  lateral  halves  by  the  mesian  line,  receive  the  same  num- 
ber of  vessels  from  either  side;  but  there  are  but  few  organs^ 
with  the  exception  of  the  eye,  the  testicles  and  kidneys, 
that  receive  many  vessels  of  each  kind.  Examined  in  those 
parts  in  which  they  are  distributed  and  pass  out,  the 
vessels  present  a  great  number  of  divisions  which  form  fre- 
quent anastomoses  wjth  each  other. 

The  most  minute  vessels,  known  by  the  name  of  capil- 
laries, are  spread  throughout  every  part  of  the  body,  as 
may  be  demonstrated  by  microscopic  inspection  and  injec- 
tions. The  smaller,  less  delicate  branches,  are  found  more 
particularly   on  the  superficjes   of  the    body;    while  the 


VASCULAR    SYSTEM.  29 

branches  are  situated  more  deeply,  and  are  embedded  in  a 
quantity  of  cellular  tissue,  which  fills  up  the  great  interstices 
of  the  organs,  particularly  in  those  regions  where  flexion  is 
performed.  The  vascular  trunks  are  found  exclusively  in 
the  cavities  of  the  thorax  and  abdomen. 

Mode  of  Division. — The  mode  of  division  of  the  vessels 
varies  in  the  different  parts  of  the  body.  Sometimes  it 
consists  in  a  bifurcation,  and  forms  branches  that  correspond 
with  each  other  in  length  and  diameter;  it  is  in  this  way 
that  the  aorta  terminates  in  the  abdomen;  most  frequently, 
however,  a  branch  is  separated  from  a  trunk,  which  con- 
tinues its  course;  in  this  case  we  observe  no  uniform  pro- 
portion between  the  volume  of  the  first  and  that  of  the 
second.  The  origin  of  the  vessels  is  commonly  near  their 
place  of  destination,  and  it  is  seldom  that  we  see  them  run 
*%iy  considerable  distance  without  furnishing  divisions:  the 
spermatic  artery  is  of  the  small  number  of  those  which 
form  exceptions  to  this  rule. 

When  they  divide,  the  vessels  form  various  angles,  but, 
most  generally,  they  are  acute,  especially  in  the  extremi- 
ties. The  divisions  of  the  great  trunks,  however,  present 
many  examples  of  right  angles,  while  the  superior  inter- 
costals,  and  recurrent  arteries  of  the  extremities  are  given 
off  at  a  very  obtuse  angle. 

Mode  of  communication. — The  different  kinds  of  ves- 
isere  communicate  with  each  other,  not  only  because  they 
result  from  the  ramifications  of  the.  same  trunks,  but  also 
from  the  connexions  called  anastomoses,  which  we  shall 
describe  in  a  subsequent  part  of  this  work. 

Two  vessels  sometimes  meet  and  unite  to  form  an  arch, 
from  the  convexity  of  which  small  branches  are  given  off, 
especially  in  the  neighbourhood  of  the  joints,  the  intestinal 
canal,  the  hand,  the  foot,  &c;  at  other  times,  the  commu- 
nication is  effected  by  means  of,  an  intermediate  branch, 
as  in  the  two  anterior  cerebral  arteries,  the  vena  cava  and 
umbilical  vein,  &c.  Two  equal  trunks  sometimes  unite  at  an 


> 


30  VASCULAR  SYSTEM. 

acute  angle,  and  form  but  one,  which  takes  a  middle  direc- 
tion between  that  of  the  original  trunks.  It  is  thus  that  the 
two  vertebral  arteries  unite  and  form  the  basilar.  All  the 
different  kinds  of  anastomoses  come  under  the  head  of  one 
of  the  varieties  which  we  have  just  noticed.  They  are  more 
frequent  in  proportion  as  the  vessels  are  smaller,  more  nu- 
merous and  superficial.  The  anastomoses  of  the  lymphatics 
are  more  numerous  than  those  of  the  veins,  and  those  of 
the  veins  than  the  arteries.  Their  principal  object  is,  to 
facilitate  the  circulation  of  the  fluids,  and  to  maintain  it 
by  means  of  collateral  passages,  when  one  of  the  principal 
vessels  has  been  obliterated:  it  is  in  this  manner  that  the  cir- 
culation is  performed,  although  some  of  the  larger  branches 
shall  have  shrunk  and  even  become  obliterated. 

Surfaces. — The  vessels  adhere  by  their  external  surfac 
to  the  surrounding  cellular  tissue,  which  is  condense 
around  them  so  as  to  form  a  sheath.  Their  internal  sur- 
face is  smooth,  even,  and  slippery,  continually  moistened 
by  a  serous  exhalation,  and  marked  by  semicircular  projec- 
tions, which  correspond  to  the  angles  that  are  formed  by 
the  branches  in  separating  from  their  trunks. 

Structure. — The  parietes  of  the  vessels  are  formed  of 
several  cylindrical  membranes,  whose  structure  and  other 
characters  differ  in  the  different  kinds  of  vessels;  we  shall 
describe  them  in  treating  of  the  history  of  each  order  of 
vessels  in  particular.  Their  coats  are  thicker  in  propor- 
tion as  their  caliber  is  smaller;  they  receive  minute  branches 
of  blood  vessels  and  lymphatics  (vasa  vasorum,)  and  their 
nerves,  which  are  derived  from  the  cerebro-spinal  centre 
and  the  great  sympathetic,  form  a  kind  of  reticulum  around 
their  external  surface. 

Physical  and  vital  properties.  The  physical  and  vital 
properties  of  the  vessels,  as  well  as  their  functions,  differ 
much,  in  the  different  kinds  of  vessels,  as  we  shall  remark 
in  the  following  sections. 


VASCULAR  SYSTEM.  31 

Mode  of  development  and  differences  according  to  age. 
— The  mode  of  development  of  the  vascular  system  has  not 
hitherto  been  examined,  either  in  man,  or  in  the  mammi- 
ferse,  and  all  the  knowledge  that  we  possess  on  this  subject 
has  been  derived  from  examining  the  eggs  of  birds.  The 
vitelline  membrane,  which  appears  to  correspond  to  the 
earachus  of  mammiferous  animals,  exhibits  at  first,  small, 
isolated  fissures,  which  are  filled  with  a  thin,  transparent 
fluid,  and  which,  as  they  increase  in  number,  assume  the 
form  of  a  small  tree  whose  trunk  appears  in  a  short  time 
after,  and  forms  the  omphalo-mesenteric  vein,  which  at  this 
period  contains  red  blood.  It  passes  from  below  upwards, 
Aon  the  anterior  surface  of  the  embryon,  dilates  and  forms 
mhe  heart;  the  arteries  are  formed  soon  after,  and  finally 
lhe  veins.  These  circumstances  would  induce  us  to  believe 
"at  the  embryon  of  the  mammiferous  animals  is  develop- 
ed in  the  following  order:  that  the  umbilical  vein  is  formed 
first,  and  that  the  development  of  the  arteries  of  the  belly 
precedes  that  of  their  corresponding  veins;  in  short,  that 
the  order  of  appearance  of  the  vessels  is  in  proportion  to 
the  increasing  quantity  of  the  fluids  which  traverse  them. 
The  organs  are  at  first  mere  hollow  canals,  embedded  in 
the  surrounding  substance,  which  is  gradually  condensed 
around  them  so  as  to  form  distinct  parietes;  so  that  they 
acquire  their  proper  texture  only  by  slow  degrees.  In  old 
age,  the  coats  of  the  vessels,  especially  those  of  the  arteries, 
become  very  condensed  and  brittle.  As  to  the  number  of 
vessels,  it  is  during  foetal  life  that  it  is  the  most  considera- 
ble; and  it  is  at  this  period  that  we  find  different  branches 
which  are  obliterated  after  birth;  such  are  the  umbilical 
vessels,  the  ductus  venosus  and  ductus  arteriosus. 

Pathological  Jinatomy. 

The  anomalies  of  origin,  situation  and  form,  are  frequent 
in  the  vascular  system;  we  shall  have  occasion  to  point  out 
some  of  them  in  speaking  of  the  different  kinds  of  vessels, 


o2  Of  THE  ARTERIES. 

We  observe  in  the  tissues,  which  have  their  analogies 
in  the  animal  economy,  as  well  as  in  cicatrices,  adhesions 
and  pseudo-membranes,  vessels  which  are  at  first  develop- 
ed separately,  like  those  of  the  urachus,  and  which  com- 
municate afterwards  with  those  of  the  contiguous  parts. 

The  pathological  anatomj-  of  the  vessels  varies  so  much 
in  the  different  kinds  of  vessels,  that  it  can  not  claim  our  at- 
tention on  the  present  occasion:  we  shall  revert  to  it  in  the 
following  sections. 


sectiox  2. 


Of  the  Arteries. 


Definition. — The  arteries  are  the  vessels  which  carry 
the  blood  from  the  heart  to  every  part  of  the  body. 

Division. — There  are  two  arterial  trees,  the  pulmonary 
and  the  general;  the  first  carries  black,  the  second  red 
blood. 

General  arrangement. — The  arterial  system  consists  of 
two  principal  trunks  which  arise  from  each  ventricle  of  the 
heart.  The  one,  called  the  pulmonary  artery,  arises  from 
the  right  ventricle,  and,  as  it  ascends,  it  divides  into  two 
branches,  one  on  either  side  of  the  aorta,  the  right  to  b*e 
ramified  on  the  right  lobes,  and  the  left  on  the  left  lobes  of  the 
lungs;  the  other,  called  the  aorta,  arises  from  the  left  ventri- 
cle, passes  upwards  towards  the  superior  part  of  the  thorax, 
furnishes  large  branches,  which  are  distributed  on  the  neck, 
head,  and  superior  extremities;  after  which,  it  forms  a  great 
curve,  descends  along  the  anterior  part  of  the  left  side  of 
the  bodies  of  the  vertebrae,  furnishes  branches  to  the  vis- 
cera of  the  abdomen,  and  divides,  between  the  fourth  and 
fifth  lumbar  vertebras  into  two  secondary  branches,  which 
are  distributed,  after  having  sent  branches  to  the  pelvic 
viscera,  on  the  inferior  extremities. 

The  arteries,  after  a  certain  number  of  divisions,  (twen- 


OF  THE  ARTERIES.  33 

ty-one  according  to  Haller  and  Bichat,)  terminate  in  the 
capillary  system,  where  they  are  continuous  with  the  ra- 
dicles of  the  veins.* 

Situation. — The  arteries  are  generally  situated  more 
deeply  than  the  veins  and  lymphatic  vessels. 

Form  and  diameter. — The  form  of  the  arteries  is  more 
uniformly  cylindrical  than  that  of  the  other  vessels,  and  their 
diameter,  ordinarily  less  than  that  of  the  veins  which  ac- 
company them,  diminishes  in  proportion  as  they  recede 
from  the  heart;  a  circumstance  not  always  observable  in  the 
veins  and  lymphatic  vessels. 

Relative  number. — The  number  of  the  arteries  is  also 
much  smaller  than  that  of  the  veins  and  lymphatic  vessels; 
thus,  each  artery  of  a  middle  size  is  generally  accompanied 
by  two  corresponding  veins  and  ten  lymphatics.  These 
differences,  however,  only  relate  to  the  general  system, 
and,  consequently,  do  not  exist  between  the  pulmonary 
arteries  and  veins. 

Course. — In  their  course,  the  great  arterial  trunks, 
generally,  follow  a  straight  direction;  the  arch  of  the  aorta 
and  the  internal  carotid  in  the  interior  of  the  osseous  canal, 
by  which  it  enters  the  cavity  of  the  cranium,  form,  how- 
ever, exceptions  to  this  rule.  The  small  arterial  branches 
and  ramifications  are  generally  more  tortuous  than  the 
veins.  r 

Anastomoses. — The  anastomoses  of  the  arteries  are  less 
numerous  than  those  of  the  veins  and  lymphatic  vessels; 
and  this  is  particularly  true  with  regard  to  the  arteries  that 
have  a  large  caliber;  the  ductus  arteriosus,  between  the  aor- 
ta and  pulmonary  artery,  in  the  foetus,  being  the  only  in- 
stance of  this  kind  of  communication  in  the  body.  Not- 
withstanding, the  anastomoses  of  the  arterial  system  are 
sufficiently  numerous  to  maintain  the  circulation  by  means 

*  Some  are  still  visible  after  they  have  changed  from  vasa  efferentia 
into  vasa  afferentia. 
6 


34  OF  THE  AttTERIES. 

of  collateral  passages,  after  the  great  trunks,  such  as  the 
abdominal  aorta,  the  iliac  and  carotid  arteries,  &c.  have 
been  obliterated  by  the  application  of  ligatures. 

Surface. — The  external  surface  of  the  arteries  is  sur- 
rounded by  a  loose  sheath  which  is  formed  by  the  conden- 
sation of  the  surrounding  cellular  tissue,  and  which  is  par- 
ticularly firm  and  dense  in  those  parts  which  are  subservient 
to  locomotion.  In  several  parts  of  the  visceral  cavities,  this 
sheath  is  wanting,  and  its  place  is  supplied  by  folds  of  the 
serous  membranes.  It  is  in  this  manner  that  the  pericar- 
dium is  spread  over  the  origin  of  the  arterial  and  venous 
trunks.  The  internal  surface  of  the  arteries  is  smooth  and 
slippery,  and,  as  we  have  already  said,  continually  mois- 
tened by  a  serous  exudation.  At  the  entrance  of  the  ven- 
tricles, it  presents  several  valves,  the  only  ones  of  the  arte- 
rial system,  and  which  we  shall  presently  describe. 

The  parietes  are  stronger  in  the  small  than  in  the  large 
arteries,  in  proportion  to  the  size  of  the  caliber,  hence 
aneurisms  are  much  less  frequent  in  the  former. 

Structure. — The  parietes  of  the  arteries  are  formed  of 
three  cylindrical  coats. 

External  coat. — The  external  coat  is  formed  by  the 
condensation  of  the  laminae  of  the  cellular  tissue  which  sur- 
rounds the  arteries  and  connects  them  to  the  neighbouring 
parts.  It  admits  of  considerable  extension,  is  the  most  re- 
sisting of  the  three,  and  the  only  one  that  is  not  divided 
when  an  artery  is  tied. 

Middle  coat. — This  coat,  which  is  sometimes  called  the 
fibrous  or  proper  coat  of  the  arteries,  is  formed  by  a  yel- 
low, very  elastic  tissue,  analogous  to  that  which  is  found 
in  the  trachea  and  yellow  ligaments  of  the  vertebras.  (See 
hist,  of  the  yellow  fibrous  tissue.)  It  consists  of  spiral 
fibres,  which  but  imperfectly  surround  the  arteries;  they 
cross  each  other  in  various  directions,  and  are  arranged  in 
layers  that  maybe  easily  separated.  These  fibres  are  strong, 
very  elastic  and  their  firmness  is  sufficient  to  maintain  the 


OF  THE  ARTERIES.  35 

caliber  of  the  arteries  when  they  are  empty.  The  middle 
coat  adheres  more  intimately  to  the  external  than  to  the  in- 
ternal; and  at  the  ventricles  of  the  heart,  it  gives  origin  to 
three  semi-circular  festoons  which  correspond  to  the  semi- 
lunar valves  that  they  support. 

Internal  coat. — The  internal  coat,  called  also  the  com- 
mon coat  of  the  arteries,  because  it  extends  into  the  cavi- 
ties of  the  heart,  is  thicker  in  the  arteries  of  the  general 
system  than  in  those  of  the  pulmonary,  and  has  no  apparent 
fibres;  it  is  thin  and  diaphanous,  eminently  brittle,  smooth 
and  even  on  its  internal  surface,  which  is  lubricated,  and, 
adhering  by  its  external  surface  to  the  middle  coat.  At  the 
entrance  of  each  ventricle,  it  forms  three  folds,  which  ad- 
here to  the  circumference  of  the  festoons  that  are  formed 
by  the  middle  coats  of  the  arteries,  and  their  floating  mar- 
gins, the  centre  of  each  of  which  is  guarded  by  a  corpus 
sesamoideum,*  present  in  the  direction  of  the  course  of 
the  blood,  and  meet  as  tense  chords,  describing  three  radii 
of  the  circular  aperture  of  the  vessel.  These  folds  are  called 
the  sigmoid  or  semilunar  valves,  and  are  of  use  in  pre- 
venting the  return  of  the  blood  from  the  arteries  into  the 
ventricles. 

We  see,  from  the  preceding  observations,  that  the  cavi- 
ties of  the  heart  are  lined  by  a  continuation  of  the  internal 
membrane  of  the  arteries,  and  also,  that  this  membrane  is 
there  confounded  with  the  venous  trunks  in  such  a  manner 
that  the  heart,  composed  in  man  of  two  lateral  halves,  may 
be  regarded  as  a  double  portion  of  the  vascular  system, 
which  differs  from  the  others  only  in  that  its  exterior  en- 
velopes, instead  of  being  fibrous  and  cellular,  are  a  net- 
work of  muscular  fibres. 

The  arteries  are  supplied  with  nerves,  blood-vessels  and 

*  This  body  serves  to  fill  up  the  space  which  is  left  between  the  free 
margins  of  the  valves,  where  they  unite  to  close  up  the  caliber  of  the 
vessels.     (See  the  Works  on  Descrip.  Anat.) 


36  OF  THE  ARTERIES. 

lymphatics.  The  nerves  are  larger  and  more  numerous  in 
the  arteries  of  the  pulmonary  than  in  those  of  the  general 
system,  and  proportionably  in  the  small  than  in  the  larger 
branches.  They  are  derived  from  the  great  sympathetic 
and  spinal  nerves. 

Characters  and  physical  properties. — The  arteries  are 
less  dense  and  resisting  than  the  veins,  but  they  are  thicker 
and  enjoy  a  greater  degree  of  elasticity,  which  is  owing  to 
their  fibrous  tunic.  This  property  of  the  arteries  is  more 
appreciable  in  the  direction  of  their  length  than  in  that  of 
their  circumference,  and  in  the  large  than  in  the  small 
arteries. 

Vital  properties. — The  sensibility  of  the  arteries  is  very 
obscure;  and  their  power  of  vital  contractility  has  been 
denied  by  a  number  of  physiologists,  especially  by  Haller, 
Bichat,  Nysten,  and  lately  by  Magendie,  who  pretends 
that  these  vessels  manifest  no  more  signs  of  irritability  un- 
der the  influence  of  mechanical  and  chemical  agents  than 
under  that  of  galvanism.  But  the  facts,  recorded  by  Zim- 
mermann,Verschuir,  Soemmering,  Hunter,  Hastings,  Parry, 
Ginglio,  Rossi  and  others,  prove  incontestibly  the  incorrect- 
ness of  the  opinions  of  those  who  have  denied  the  vital  con- 
tractility of  the  arteries;  and  at  the  present  day,  most  physio- 
logists arc  of  opinion,  first,  that  the  arteries  contract;  se- 
condly, that  this  action  is  more  remarkable  in  proportion  as 
their  caliber  is  smaller  and  their  elasticity  less. 

The  contractility  of  the  arteries  is  rendered  evident  by 
their  beats  or  pulsations,  which  constitute  what  is  called  the 
pulse;  a  phenomenon  resulting  not  only  from  the  motion 
or  slight  displacement  of  these  vessels,  caused  by  the  shock 
which  the  blood  receives  from  the  sudden  impulse  of  the 
ventricles,  but  also  from  the  dilatation  and  contraction  of 
their  parietes  in  consequence  of  the  intermittent  afflux  of 
this  fluid.*     Each  of  these  two  kinds  of  movements  has 

•  By  attentively  observing  each  pulsatory  motion,  it  can  be  demon- 


OF  THE  ARTERIES.  37 

been  considered,  in  its  turn,  as  the  exclusive  cause  of  the 
pulsations  of  the  arteries,  but  it  has  been  demonstrated  that 
they  are  the  result  of  the  combined  actions  of  both,  and 
that  the  first  predominates  in  the  great  trunks,  and  the  se- 
cond in  the  branches  and  ramifications.  The  pulsations  of 
the  arteries  correspond,  in  general,  with  the  contractions 
of  the  heart;  and  it  is  from  these  circumstances,  that  the 
pulse  has  furnished  us  with  one  of  the  most  important 
sources  of  diagnosis  in  the  examination  of  diseases.  Its 
fulness,  its  development,  its  frequency,  its  quickness,  its 
regularity,  its  equality,  as  well  as  its  opposite  qualities, 
afford  us  the  means  of  judging  of  the  danger  and  degree  of 
intensity  of  the  different  diseases  with  which  man  is  liable 
to  be  afflicted.  In  some  inflammations,  especially  in  those 
of  a  phlegmonous  character,  the  pulsations  of  the  arteries  of 
the  part  affected,  are  generally  somewhat  accelerated,  in- 
dependently of  the  actions  of  the  ventricles.  We  observe 
also,  that  in  paralytic  patients,  the  pulse  is  more  feeble 
in  the  limbs  that  are  deprived  of  motion  than  in  the  other 
parts;  another  proof  of  the  contractility  of  the  arteries. 

Functions.— r-The  arteries  receive  the  blood  from  the 
heart  and  carry  it  to  every  part  of  the  body.  The  motion 
of  the  blood  is  by  no  means  uniform;  each  cantraction  of 
the  ventricles  gives  a  propelling  motion  to  its  mass,  which 
may  be  readily  observed  when  an  artery  is  divided;  the 
blood  then,  it  is  true,  will  be  seen  to  flow  without  inter- 
ruption, but  by  jets  and  jerking  motions,  which  are  syn- 
chronous, like  the  pulse,  with  the  contractions  to  which 
we  have  just  alluded. 

When  the  collateral  branches  of  a  large  artery  receive  a 
larger  quantity  of  blood  than  is  natural,  their  calibers  be- 
come considerably  enlarged,  not  only  by  the  dilatation  of 
their  parietes,  but  by  an  actual  increase;  for  it  must  be  re- 
stated that  there  is  a  simultaneous  elongation  and  dilatation,  followed 
by  a  shortening-  and  contraction  of  the  arteries, 


38  OF  THE  ARTERIES. 

membered,  that  the  parietes  of  an  artery  do  not  necessarily 
diminish  on  account  of  their  development.  On  the  con- 
trary, the  artery  which  has  ceased  to  be  traversed  by  the 
blood,  shrinks,  and  is  finally  obliterated  and  converted  into 
a  kind  of  ligamentous  cord:  we  shall  not  say  that  this  is 
the  result  of  its  contractility,  but  a  consequence  of  the  ces- 
sation of  its  functions,  the  chief  effect  of  which  is,  a  dimi- 
nution in  the  activity  of  nutrition. 

Differences  according  to  age. — The  arteries  are  pro- 
portionably  more  elastic  and  more  fully  developed  in  in- 
fancy and  youth  than  at  any  other  period  of  life.  In  the 
decline  of  life,  they  lose  their  elasticity  and  become  more 
and  more  brittle,  and  their  ossification,  which  takes  place 
at  this  period,  may  be  regarded  as  a  normal  state,  intend- 
ed by  nature  to  give  strength  to  their  middle  coat,  which 
is  its  ordinary  seat.  In  old  age,  the  parietes  of  the  great 
trunks  are  thin  and  brittle,  especially  those  of  the  general 
system. 

Anomalies  of  origin. — Bichat,  and  since  his  time, 
Meckel  and  Beclard  have  observed  that  the  anomalies  of 
origin  of  the  arteries  are,  in  proportion  to  their  number 
and  volume,  at  least  as  frequent  as  those  of  the  veins.* 
Meckel  has  seen  ten  anomalous  origins  from  the  arch  of 
the  aorta,  while  he  has  known  but  one  from  the  vena  cava 
superior.  This  author  has  made  a  similar  remark  with  re- 
gard to  the  arteries  and  veins  of  the  extremities. 

Pathological  Anatomy. 

The  arteries  are  subject  to  changes  of  form  without  lesion 
of  their  tissue.  Thus,  their  volume  may  enlarge,  either 
throughout  their  whole  length,  as  parts  that  have  been  a 
long  time  inflamed,  present  examples,!  or  only  in  a  part  of 

*  Haller,  Soemmering,  and  the  Walthers,  have  asserted  the  contrary, 
f  In  this  case,  the  thickness  of  the  parietes  corresponds  to  the  dilata- 
tion as  in  the  deyelopment  of  the  collateral  branches. 


OF  THE  ARTERIES.  39 

their  extent.  When  the  dilatation  is  local,  (the  true  aneu- 
rism of  the  ancients,)  it  occupies  either  the  entire  circum- 
ference of  the  vessel,  or,  as  is  most  frequently  the  case, 
only  a  part  of  it.  The  arteries  are  also  subject  to  mor- 
bid contractions,  which  may  be  either  general  or  partial; 
the  first  may  be  observed  to  take  place,  particularly  in 
those  parts  where  the  vital  action  is  languid  and  feeble; 
the  second,  more  common  in  the  great  trunks,  are  some- 
times the  result  of  a  local  alteration  of  the  tissue  of  the  ar- 
tery. Inflammation  of  the  arteries  is  characterized  by  red- 
ness, and  sometimes  a  thickening  of  their  internal  coat, 
and  an  effusion  of  coagulating  lymph,  which  produces  an 
adhesion  of  their  parietes  when  they  are  brought  in  contact 
by  compression,  ulceration,  gangrene,  &c.  '  The  internal 
coat  is  the  most  subject  to  inflammation;  the  external  re- 
sembles it  in  this  respect,  and  when  inflamed,  it  is  ren- 
dered exceedingly  brittle.  Fungous  growths  are  not  unfre- 
quent  on  the  surface  of  the  internal  coat,  especially  in  the 
neighbourhood  of  the  valves.  There  are  sometimes  small 
encysted  tubercles  between  this  and  the  middle  coat  of  the 
arteries,  which  terminate  either  by  suppuration  or  ossifica- 
tion, so  as  to  obstruct  the  caliber  of  the  vessel.  Ossification, 
so  frequent,  as  we  have  just  remarked  in  old  people,* 
may  also  be  observed  sometimes  to  occur  in  adults;  it  is 
often  confounded  with  earthy  concretions,  which  are  form- 
ed between  the  middle  and  internal  coats,  and  enter  the 
caliber  of  the  artery  by  penetrating  its  internal  membrane. 
In  consequence  of  the  local  dilatation  of  a  part  of  the  circum- 
ference of  an  artery,  but  more  frequently  without  any  pre- 
vious dilatation,  the  internal  coats  being  weakened  from  the 
constant  impulse  of  the  blood,  or  altered  in  their  texture, 
give  way  and  break.  The  cellular  coat  then  becomes  distend- 
ed, and  forms  a  tumour  on  the  sides  of  the  artery,   with 

*  It  is  to  this  circumstance  that  must  be  attributed  the  ordinary  cause 
of  the  spontaneous  gangrene  known  under  the  name  of  gangrena  senilis. 


40  OF    THE  ARTERIES. 

which  it  communicates  by  a  ragged,  and  irregular  open- 
ins.  This  constitutes  what  is  termed  the  true  aneurism — 
one  of  the  most  dangerous  diseases  of  the  arteries,  and  even 
of  the  animal  economy.  The  ancurismal  cavity  contains 
coagula  of  blood,  and  its  parietes  are  frequently  lined  with 
fibrous  layers  and  pseudo-membranes.  The  tumour  some- 
times remains  stationary,  after  having  attained  to  a  cer- 
tain size;  but  more  frequently  it  goes  on  gradually  in- 
creasing, and  demands  the  interference  of  the  surgeon.  It 
is  seldom,  indeed,  that  we  see  it  diminish  in  consequence 
of  spontaneous  obliteration,  and  to  induce  this  effect  it  is 
almost  always  necessary  to  obtain  surgical  aid.  This  dis- 
ease presents  so  many  varieties,  that  we  shall  necessarily  be 
obliged  to  pass  some  of  them  unnoticed  on  the  present  oc- 
casion. The  great  trunks,  and  the  large  branches,  espe- 
cially those  of  the  inferior  extremities,  are  the  most  ordi- 
nary seat  of  this  affection.  False  aneurism  is  a  tumour 
formed  by  the  effusion  of  blood  into  the  adjoining  cellular 
tissue,  either  immediately  after  a  wound,  or  in  consequence 
of  the  rupture  of  a  cicatrix,  (primitive  false  an. — consecu- 
tive false  aneurism.) — Ligatures  applied  around  healthy  ar- 
teries, divide  the  internal  and  middle  coats,  whilethe  exter- 
nal resists  the  cause  of  rupture,  by  dilating,  and  forms  a  tu- 
mour:— the  blood  is  next  arrested  in  its  progress,  and  forms 
a  coagulum  between  the  ligature  and  the  nearest  collateral 
branch;  inflammation  supervenes,  and  at  the  end  of  forty- 
eight  hours  it  determines  the  adhesion  of  the  coats  of  the 
artery  by  means  of  an  effusion  of  coagulating  lymph,  then 
the  division  of  the  tissues  that  embraced  the  ligature,  its 
separation  and  removal,  and  finally  the  absorption  of  the 
clot,  followed  by  the  obliteration  of  the  part  of  the  artery 
which  it  filled.  In  cases  where  the  external  coats  are  bro- 
ken, and  the  internal  coat  alone  remains  entire,  cicatriza- 
tion is  also  produced  by  the  effusion  of  coagulating  lymph, 
which  increases  the  thickness  of  the  parietes  of  the  artery, 
and  gives  additional  strength  to  its  internal  membrane;  at 


OF  THE  ARTERIES.  41 

other  times,  the  internal  coat  is  distended,  forms  a  tumour 
across  the  solution  of  continuity  of  the  others,  and  consti- 
tutes what  is  called  the  internal  mixed  aneurism. 

From  the  beautiful  experiments  performed  upon  dogs, 
by  Jones  and  Beclard,  with  a  view  to  determine  the  rela- 
tive degree  of  danger  resulting  from  wounds  of  the  differ- 
ent coats  of  the  arteries,  it  appears,  first,  that  a  very  small 
puncture  of  an  artery  is  followed  by  a  slight  degree  of 
hemorrhage,  by  the  formation  of  a  coagulum  which  closes 
up  the  mouth  of  the  wound,  and  by  a  complete  cicatriza- 
tion; secondly,  that  all  other  wounds  of  the  arteries  are 
fatal,  if  the  cellular  coat  has  been  destroyed,  excepting  in 
the  following  cases:  1st,  a  longitudinal  wound  heals  like  a 
simple  puncture,  but  there  remains  a  linear  cicatrix;  2d, 
a  transverse  wound  embracing  only  one  fourth  of  the  cir- 
cumference of  the  vessel,  is  susceptible  of  healing;  3d, 
when  it  occupies  one  half,  it  is  followed  by  too  great  a 
separation  of  the  edges  of  the  wound,  to  permit  of  the  forma- 
tion of  a  cicatrix;  it  must  then  necessarily  prove  fatal;  4th, 
when  it  occupies  three  fourths  of  the  vessel,  it  may  heal,  if 
the  retraction  of  its  extremities  is  sufficiently  strong  to  ac- 
complish a  solution  of  continuity;  5th,  when  this  is  com- 
plete, the  extremities  retract  within  their  cellular  sheath, 
and  after  a  profuse  hemorrhage,  syncope  ensues,  a  coagu- 
lum is  formed,  and  cicatrization  takes  place.  In  the  human 
subject,  the  treatment  of  wounds  of  the  arteries  has  hither- 
to been  attended  with  little  success;  both  on  account  of  the 
difficulty  of  checking  the  hemorrhage,  and  of  the  want  of 
firmness  in  their  cicatrices.  Gun-shot  wounds,  and  those 
resulting  from  severe  burns,  however,  seldom  bleed  pro- 
fusely, the  blood  being  retained  by  the  eschars,  which  are 
not  detached  until  after  the  obliteration  of  the  artery.  We 
shall  say  but  little  of  lacerated  wounds,  in  which  the  rup- 
ture of  the  coats  of  the  arteries  having  taken  place  in  suc- 
cession from  the  internal  to  the  external,  gives  a  conical 
form  to  the  extremity  of  the  vessel,  which,  added  to  the 


42  OP   THE    CAPILLARY   VESSELS. 

retraction  by  which  the  division  of  the  artery  is  followed, 
presents  a  sufficient  obstacle  to  the  hemorrhage  to  allow  of 
the  formation  of  a  coagulum. 


section  3. 
Of  the  Capillary  Vessels. 

Definition. — The  capillary  vessels  are  formed  by  the 
termination  of  the  arteries  and  the  commencement  of  the 
veins. 

The  smaller  ramifications  of  the  vessels  take  the  name  of 
capillaries  the  moment  that  their  tenuity  becomes  such  as  to 
be  invisible  to  the  naked  eye.  The  most  delicate  that  can 
be  distinguished  with  the  aid  of  the  microscope  present  the 
diameter  of  a  globule  of  blood,  which,  according  to  the  ex- 
periments of  Messrs.  Prevost  and  Dumas,  is  equivalent  to 
the  1-2S00  part  of  an  inch. 

Division. — The  capillary  vessels  may  be  divided  into  those 
of  the  pulmonary  and  those  of  the  general  system;  the  first 
being  between  the  termination  of  the  pulmonary  arteries 
and  veins,  is  distributed  on  the  surface  of  the  air-cells  of 
the  lungs,  where  the  blood  which  circulates  through  it  is 
changed  from  venous  to  arterial;  while  the  second,  which  is 
between  the  terminations  of  the  aortic  arteries  and  the  origin 
of  the  veins  ofthebody,is  disposed  in  different  proportions  to 
the  compound  solids  of  the  body,  and  the  blood  which  cir- 
culates through  it  is  changed  from  arterial  to  venous.  We 
shall  speak  more  particularly  of  the  physiological  functions 
which  belong  to  each  of  these  two  divisions,  in  a  subsequent 
part  of  this  section.  Besides  the  two  divisions  just  men- 
tioned, there  is  a  venous  capillary  system,  which  is  form- 
ed by  the  terminations  of  the  vena  porta?  and  the  com- 
mencement of  the  hepatic  veins. 

General  conformation. — The  capillary  vessels  form  a 
large  and  beautiful  net- work  in  the  tissues  of  our  organs; 


OF  THE    CAPILLARY  VESSELS.  43 

and  in  proportion  as  they  divide,  they  present  a  successive 
decrease  in  their  small  arterial  ramifications,  and  a  corres- 
ponding increase  as  they  unite  to  form  the  commencement 
of  the  veins. 

Situation. — The  capillary  vessels  are  spread  through- 
out every  part  of  the  body,  and  form,  by  their  union,  the 
most  extensive  part  of  the  vascular  system.  Many  phy- 
siologists, during  the  last  centuries,  have  supposed  that  our 
organs  were  formed  exclusively  of  capillary  vessels;  but 
this  opinion  has  not  yet  been  proved,  nor  completely  re- 
futed, since  we  have  no  other  means  of  proving  the  exist- 
ence of  the  sevessels  than  injection — an  art  which  has  not 
hitherto  been  fully  adequate  to  demonstrate  them  in  every 
part  of  the  body.  Inflammation,  it  is  true,  may  afford  us 
some  aid  in  elucidating  this  important  question,  since  it  is 
attended  even  in  some  of  those  tissues  which  can  not  be  in- 
jected, such  as  the  cartilaginous,  &c.  with  a  red  and  striated 
appearance,  though  it  is  doubtful  whether  these  striae  are 
any  thing  else  than  simple  hollow  canals,  formed  accident- 
ally in  the  substance  of  the  organ  that  is  inflamed.  It  re- 
mains then  for  us  to  examine  the  differences  which  exist 
between  the  different  tissues  in  regard  to  the  extent  and 
number  of  the  capillary  vessels  that  can  be  demonstrated 
by  injection.  We  may  arrange  them  in  the  following  or- 
der: first,  into  those  tissues  that  can  not  be  injected, 
which  are; — the  cellular  tissue,  the  cartilages,  the  epidermis 
and  its  appendages.  Secondly,  into  those  that  can  he  but 
partially  injected,  viz:  the  medullary  substance  of  the 
brain  and  nerves,  the  fibrous  system,  except  the  periosteum 
and  dura  mater,  the  serous  membranes  and  bones;  thirdly, 
into  those  that  can  be  readily  injected;  these  are  the  adi- 
pose vesicles,  the  cineritious  substance  and  neurilema  of  the 
nerves,  the  nervous  ganglia,  the  muscles,  but  particularly 
the  teguments,  the  glands  and  glandiform  bodies.  The 
lungs  are,  of  all  the  organs,  those  which  are  the  most  abun* 
dantly  supplied  with  capillary  vessels. 


14  OF  THE    CAriLLARY    VESSELS 

Mode  of  communication. — The  beautiful  and  well-con- 
ducted experiments  of  Leuwenhoeck,  performed  upon  the 
mesenteries  of  frogs,  the  tails  of  fishes  and  other  transpa- 
rent organs,  have  fully  and  satisfactorily  demonstrated  the 
continuity  of  the  arterial  and  venous  capillaries:  it  has  also 
been  proved  by  injections,  which  may  be  readily  thrown 
from  the  one  into  the  other.  The  parenchymatous  or  spongy 
tissue,  supposed  by  the  ancients  and  some  of  the  modern 
physiologists  to  intervene  between  the  extremities  of  the 
arteries  and  the  origin  of  the  veins,  has  never  been  demon- 
strated, and  all  that  has  been  said  concerning  it  appears  to 
be  without  foundation.  We  find  in  the  reciprocal  relations 
of  the  arterial  and  venous  capillaries,  the  three  kinds  of 
communication,  which  we  pointed  out  in  speaking  of  anas- 
tomoses in  general.  If  we  examine  an  injected  serous  sur- 
face, whose  capillaries  have  been  carefully  and  minutely 
filled,  we  shall  see  that  this  system  presents  a  complete  net- 
work with  fine  meshes,  in  which  no  vessels  run  a  distance  of 
more  than  two  lines  without  anastomosing  with  others. — 
The  lymphatic  vessels  anastomose  freely  with  the  veins; 
but  it  is  as  yet  doubtful  whether  they  form  any  anastomoses 
with  the  arteries. 

Structure. — The  parietes  of  the  capillary  vessels  can 
scarcely  be  distinguished  from  the  substance  of  the  sur- 
rounding organs,  and  all  our  knowledge  of  their  texture 
consists  in  the  mere  supposition  that  they  are  formed  by 
a  continuation  of  the  internal  membrane  of  the  arteries  and 
the  veins.  They  are  interwoven  with  nervous  filaments 
which  are  derived  from  the  cerebro-spinal  system  and  the 
great  sympathetic  nerve;  and,  it  is  from  an  assemblage  of 
these,  that  the  papillas  of  the  skin  and  mucous  membranes 
are  formed. 

Hypotheses  of  different  authors  with  respect  to  the  ex- 
istence of  serous  vessels,  &>-c. — Boerhaave,  and  those  who 
embraced  the  idea  that  our  organs  were  entirely  composed 
of  vessels,  have  thought,  as  well  as  many  anatomists,  such 


OV  THE    CAPILLARY   VESSELS.  45 

as  Haller,  Soemmering,  Bichat  and  Chaussier,  that  there 
was  a  set  of  vessels  that  were  more  delicate  than  the  visi- 
ble capillary  terminations  with  which  they  were  continu- 
ous, and  which  admitted  only  the  serum  of  the  blood. 
Boerhaave  even  went  so  far  as  to  classify  them  into  several 
orders.  The  facts  upon  which  this  opinion  rests  have  been 
drawn  from  the  following  observations:  first,  from  the  cir- 
cumstance that  we  can  not  form  any  idea  of  the  manner  in 
which  nutrition  takes  place  in  those  organs  that  can  not  be 
penetrated  by  injections;  and  secondly,  from  the  fact  that 
those  parts  which  are  naturally  white,  become  red  the  mo- 
ment they  are  in  a  state  of  inflammation.  Bleuland  is  said 
once  to  have  seen  a  set  of  pellucid  vessels  that  arose  from 
the  terminations  of  the  arterial  capillaries. — To  the  obser- 
vations advanced  by  the  above  physiologist,  it  will  be  suffi- 
cient to  remark;  first,  that  with  the  aid  of  a  powerful  mi- 
croscope, the  terminations  of  the  vessels  can  be  rendered 
sufficiently  apparent,  inasmuch,  that  if  there  were  even  a 
set  of  vessels  more  minute  than  the  capillaries,  they 
would  necessarily  be  rendered  evident;  secondly,  that  we 
can  perceive  the  vascularity  of  an  organ  by  coloured  injec- 
tions, since  the  capillaries  which  admit  only  a  single  glo- 
bule of  blood  at  the  time,  appear  perfectly  transparent; 
whence  it  is  natural  to  conclude,  that  if  a  trasparent  organ 
becomes  red  when  inflamed,  it  is  owing,  in  part,  to  the  irri- 
tation which  increases  the  capacity  of  the  capillary  vessels, 
so  as  to  admit,  consequently,  a  greater  number  of  globules 
at  the  time;  thirdly,  that  the  inflammatory  blush  is  often  the 
result  of  the  injection  of  the  whole  substance  of  an  organ. 
In  summing  up  the  facts  of  the  preceding  observations,  it 
will  be  seen,  that  the  serous  vessels  have  been  observed 
but  a  single  time,  and  that  they  ought  not,  from  the  expe- 
riments of  Bleuland,  to  be  considered,  in  the  present  state 
of  our  knowledge,  as  a  separate  system. 

Many  anatomists  admit  the  existence  of  extremely  fine 
vessels,  endowed  with  the  power  of  transmitting  from  the 


46  OF  THE  CAPILLARY  VESSELS. 

arteries,  the  materials  of  nutrition,  and  of  exhalation,  and 
of  other  capillaries  equally  delicate,  whose  office  it  is  to  take 
up  and  carry  into  the  veins  the  exhalations  and  organic  par- 
ticles which  are  destined  to  re-enter  the  circulation.  The 
first  of  these  are  called  the  exhalent  and  nutrient  vessels, 
and  the  second  the  absorbejits;  but  the  existence  of  these 
intermediate  agents  has  never  been  demonstrated  by  ex- 
periment, nor  the  open  mouths  of  the  capillary  vessels,  ad- 
mitted by  some  anatomists,  who  have  attributed  to  them 
the  functions  to  which  we  have  just  alluded.  None  of 
these  hypotheses  are,  however,  necessary  to  the  theory  of 
absorption,  and  of  exhalation;  these  being  performed  to  a 
greater  or  less  extent  in  all  the  tissues  of  the  animal  econo- 
my, and  are  a  natural  consequence  of  their  hygromitricitL 

Physical  and  vital  properties. — The  capillary  vessels 
are  exceedingly  permeable;  their  sensibility  varies  in  the 
different  organs  in  which  they  are  found,  and  their  con- 
tractility is  greater  and  more  conspicuous  than  in  the  other 
parts  of  the  vascular  system. 

Functions. — The  circulation  of  the  blood  in  the  capilla- 
ry vessels  is  performed  by  the  immediate  action  of  the 
heart,  and  by  their  own  contractile  power.  Having  al- 
ready pointed  out  the  differences  that  exist  between  the 
pulmonary  and  the  general  capillary  systems,  with  regard 
to  the  change  of  colour  which  the  blood  suffers  in  traversing 
them,  it  may  not  be  amiss  to  speak  a  little  more  in  detail. 
In  its  passage  through  the  capillaries  of  the  lungs  the  blood 
is  brought  into  contact  with  the  atmospheric  air,  absorbs  its 
oxigen,  and  exhales  a  small  quantity  of  serosity,  which  is 
discharged  during  the  act  of  expiration.  Moreover,  the 
capillaries  which  arise  from  the  ramifications  of  the  aorta, 
carry  red  blood,  deposit  into  all  the  organs  the  materials  of 
nutrition,  losing  in  some  of  them  those  parts,  which,  be- 
ing separated  by  simple  exhalation,  or  by  glandular  secre- 
tion, either  re-enter  the  vascular  systems  (recrementitial 
fluids,)  or  are  thrown  off  from  the  economy  (excrementitial 


OF  THE  CAPILLARY  VESSELS.  47 

fluids;)  then  becoming  venous  capillaries,  for  the  circula- 
tion of  black  blood,  they  absorb  the  recrementitial  pro- 
ducts which  result  from  the  functions  just  mentioned,  and, 
the  remains  of  nutrition. 

Erectile  tissue.  This  tissue,  which  Beclard  and  several 
modern  anatomists,  have  described  separately,  under  the 
name  of  the  erectile  tissue,  is  nothing  but  a  variety  of  the 
vascular  reticular  tissue,  and  is  formed  by  a  net-work  of 
veins  which  are  continuous  with  the  arteries,  and  which,  by 
their  frequent  anastomoses,  form  cells  which  communicate 
with  each  other.  This  tissue  is  well  developed  in  some  of 
the  organs,  especially  in  the  corpus  cavernosum  penis,  the 
clitoris,  the  nymphse,  the  nipple,  the  papillae  of  the  tegu- 
mentary  membranes,  the  spleen,  &c;  it  is  plentifully  sup- 
plied with  nerves,  and  is  supported  by  an  elastic  fibrous 
envelope.  When  its  sensibility  is  exalted,  it  becomes  the 
seat  of  a  sanguineous  fluxion,  which  lasts  as  long  as  the 
excitement  that  induced  it  continues  to  exist,  and  consti- 
tutes what  is  termed  temporary  erection:  this  phenomenon 
is  produced  in  the  sexual  organs  by  the  venereal  desire,  by 
degustation  in  the  papilla?  of  the  tongue;  and  by  the  cold 
stage  of  intermittent  fevers,  and  a  variety  of  other  causes 
in  the  spleen. 

Pathological  Anatomy. 

The  caliber  of  the  capillary  vessels  greatly  enlarges 
whenever  they  are  called  to  perform,  by  their  anastomoses, 
the  functions  of  an  obliterated  vessel.  They  are  found 
every  where  in  the  accidental  tissues,  as  in  the  pseudo- 
membranes  and  cicatrices,  &c.  In  some  parts,  especially 
under  the  skin,  they  are  developed  so  as  to  form  masses, 
varying  in  size,  configuration,  and  colour,  resembling  the 
vascular  meshes  of  the  erectile  tissue,  and,  like  them,  are 
susceptible  of  temporary  fluxion.  This  affection,  termed  te- 
langiectasia, or  aneurism  by  anastomoses,  is  generally 
of  a  congenital  nature;  and  is  vulgarly  attributed  to  the 


48  OF  THE  CAPILLARY  VESSELS. 

longing  of  the  mother  during  pregnancy.  To  these  pre- 
ternatural dilatations  may  he  referred  those  which  consti- 
tute what  are  called  hemorrhoidal  tumours. 

As  soon  as  the  capillary  vessels  are  irritated,  there  is  an 
afflux  of  blood  which  distends  their  caliber,  and  imparts  a 
red  colour  to  the  affected  tissues,  whose  volume  becomes 
sensibly  augmented.  Sometimes  these  vessels  are  ruptured, 
and  produce  considerable  hemorrhage,  as  the  blood  is  ef- 
fused into  the  surrounding  substance,  and  forms  what  is 
termed  a  spontaneous  ecchymosis;  at  other  times,  the  red- 
ness and  swelling  become  more  considerable;  the  tempera- 
ture of  the  part  is  elevated,  and  is  accompanied  with  con- 
siderable pain  and  throbbing:  this  assemblage  of  pheno- 
mena constitutes  inflammation — a  morbid  state  which  va- 
ries in  its  effects  and  termination.  Inflammation  of  the  ca- 
pillaries sometimes  terminates:  first,  either  in  resolution, 
or  by  an  effusion  of  lymph,  which  remains  either  fluid,  or 
coagulates  so  as  to  form  false  membranes,  or  it  combines 
with  the  surrounding  cellular  tissue,  and  gives  rise  to  tho 
white  induration,  and  to  all  the  changes  of  tissue  which 
this  kind  of  induration  is  capable  of  producing;  secondly, 
by  an  effusion  of  pure  blood  which,  by  its  intimate  union 
with  the  parietes  of  the  capillary  vessels,  and  the  neigh- 
bouring tissues,  produces  the  alteration  of  structure  called 
the  red  induration  (induration  rouge;)  this  morbid  altera- 
tion is  often  found  in  the  lungs,  organs  which  are  essential- 
ly vascular,  and  where,  from  its  resemblance  to  the  sub- 
stance of  the  liver,  it  is  called  hepatization;  thirdly,  by 
the  secretion  of  pus,  possessing  all  the  properties  and  dis- 
tinctive characters  which  we  pointed  out  in  speaking  of  the 
cellular  tissue.  Inflammation  also  terminates  sometimes 
in  gangrene  of  the  capillary  vessels,  and  of  the  organs  in 
which  thev  are  found.  Fungous  tumours  and  most  of  the 
diseases  said  to  be  organie  are  owing  to  long  and  constant 
irritation  of  these  vessels. 


OP  THE  VEINS.  49 

SECTION  4. 

Of  the  Veins, 

Definition. — The  veins  are  the  vessels  which  return  the 
blood  from  the  capillaries  of  the  different  parts  of  the  bo- 
dy to  the  auricles  of  the  heart. 

Division. — Besides  the  two  trees,  that  correspond  to  those 
which  compose  the  arterial  system,  the  veins  have  a  third, 
called  the  vena  port se  which  is  formed  by  the  union  of  the 
veins  of  the  spleen,  and  of  the  whole  digestive  apparatus, 
and  is  ramified  in  the  substance  of  the  liver  like  an  artery. 
The  general  venous  system  may  also  be  divided  into  the 
superficial  and  deep  seated. 

General  Conformation. — The  veins,  like  the  arteries, 
represent  the  figure  of  a  tree  whose  trunk  is  the  heart. 

Comparative  situation. — The  situation  of  the  veins  is 
generally  more  superficial  than  that  of  the  arteries; — 
striking  examples  of  this  remark  are  afforded  by  the  sub- 
cutaneous veins,  and  even  by  some  of  the  deep-seated,  as 
in  those  of  the  brain.  Course. — The  course  of  the  veins  is 
not  so  tortuous  as  that  of  the  arteries — a  circumstance 
which  materially  contributes  to  facilitate  the  course  of  the 
blood,  which  traverses  most  of  these  vessels  against  its 
own  gravity.  Number. — The  arteries  are  almost  universal- 
ly accompanied  by  two  veins,  seldom  by  one,  which  tra- 
verse with  them  the  same  osseous  openings,  and  the  same 
interstices  of  the  soft  parts.  *  We  have  already  seen  that 
the  number  of  the  veins  is  much  greater  than  that  of  the 
arteries;  this  observation,  though  true  in  a  general  point  of 
view,  is  not,  however,  applicable  to  the  sanguineous  vessels 
of  each  organ  considered  separately;  for  the  intestinal  ca- 

*  In  the  lungs,  the  intestines,  &c.  the  small  veins  are  folded  upon  the 
arterial  ramuscles  with  which  they  are  continuous,  and  follow  for  a  con- 
siderable distance  their  mode  of  "arborisation." 
8 


50  OF  THE  VEINS. 

nal,  the  kidneys,  the  testicles,  &c,  have  each  an  equal  num- 
ber of  arteries  and  veins,  while  the  penis,  the  clitoris,  the 
gall-bladder,  and  the  umbilical  cord,  have  each  two  arte- 
ries and  only  one  vein;  in  these  cases,  however,  the  size  of 
the  veins  is  much  greater  than  that  of  the  arteries  and  com- 
pensates for  the  inferiority  of  number.  Origin  and  vol- 
ume.— The  veins,  arising  in  every  part  of  the  body,  by  in- 
numerable microscopic  radicles,  which  are  continuous  with 
the  arteries,"5  unite  in  succession  and  form  ramifications, 
then  branches,  and  finally  large  trunks.  When  two  veins 
meet,  they  unite  and  form  one  that  is  smaller,  compared 
with  each  of  the  original  branches,  than  a  bifurcated  artery, 
considered  in  relation  to  one  of  its  divisions.  Sometimes, 
there  are  even  veins  whose  caliber  is  not  greater  than  the 
branches  from  which  they  are  derived; — a  kind  of  anomaly 
more  common  in  the  most  dependent  parts  of  the  body,  be- 
cause there  the  blood,  circulating  slowly  and  against  its  own 
gravity,  exerts  a  greater  degree  of  force  on  the  parietes  of 
the  veins,  naturally  very  extensible,  in  proportion  as  the  co- 
lumnwhichisseparatedfromtheheart,  is  more  considerable. 
Capacity. — The  capacity  of  the  venous  tree  is  greater  than 
that  of  the  arterial,  but  not  in  the  same  proportion  in  every 
period  of  life;  for  in  infancy,  their  capacity  is  nearly  equal, 
while  as  we  advance  in  life,  it  becomes  more  and  more  re- 
markable, and  extremely  great  in  old  age.  This  difference 
probably  exists  only  in  the  general  system  of  the  sanguine- 
ous vessels,  and  not  in  the  pulmonary. 

Anastomoses. — The  anastomoses  of  the  veins  are  ex- 
tremely numerous,  and  may  be  observed  to  take  place  even 
between  the  large  trunks;  thus  the  two  vense  cavse  commu- 
nicate with  one  another  by  means  of  the  azygos.     They 

*  The  transudation  on  the  internal  surface  of  the  intestines,  of  the  mat- 
ter of  injection  in  the  veins,  has  led  to  the  opinion  entertained  by  some 
physiologists,  that  there  are  venous  radicles  that  originate  in  open 
mouths.  The  reality  of  this  anatomical  fact,  however,  has  by  no  means 
been  proved. 


OF  THE  VEINS.  51 

are  more  frequent  in  those  parts  where  the  circulation  of  the 
blood  is  the  least  favoured,  and  where  it  maybe  interrupt- 
ed by  external  agents,  as  in  the  subcutaneous  veins,  which 
communicate  so  often  as  to  form  a  kind  of  net-work  with 
large  meshes.*  There  are  also  anastomotic  communica- 
tions between  the  superficial  and  deep  seated  veins,  which, 
according  to  Bichat,  "  are  more  necessary  in  man,  than 
in  any  other  animal,  on  account  of  the  pressure  of  his 
clothes,"  &c. 

Form. — The  veins  are  less  uniformly  cylindrical  than  the 
arteries,  a  circumstance  which  must  be  attributed  in  a  great 
measure  to  the  facility  with  which  they  can  be  distended. 
On  the  external  surface  of  some  of  them  there  is  a  kind 
of  aponenrotie  rings  ,  which  correspond  to  the  internal 
folds  or  valves,  which  we  shall  presently  describe. 

Structure. — The  parietes  of  the  veins  are  thinner  than 
those  of  the  arteries,  and  like  theirs  are  composed  of  three 
coats,  which  are  contained  in  a  sheath  common  to  all  the 
vessels.  The  sinuses  of  the  brain,  which,  until  the  time 
of  Bichat,  were  regarded  as  being  entirely  composed  of  du- 
plicatures  of  the  dura  mater,  were  proved  by  this  great 
anatomist  to  be  lined  by  a  continuation  of  the  internal 
membrane  of  the  veins. 

External  coat. — The  external  or  cellular  coat  is  less 
dense  and  resisting  than  that  of  the  arteries,  and  when 
isolated,  does  not,  like  theirs,  retain  its  cylindrical  form;  it 
is  intimately  united  to  the  middle  coat,  in  the  thickness  of 
which  it  sends  prolongations  which  extend  as  far  as  thg  in- 
ternal membrane. 

Middle  coat. — The  middle  coat  of  the  veins  is  so  thin 
and  indistinct,  that  its  existence  has  been  denied  by  some 
very  able  and  skilful  anatomists;  it  is  most  conspicuous  in 
the  subcutaneous  veins  and  in  the  great  venous  trunks, 
especially  in  the  venae  cavse;  is  of  a  loose  texture  and  is  com- 

*  The  spermatic  veins  and  those  of  the  pelvis  also  present  a  retiform 
arrangement. 


52  OF  THE  VEINS. 

posed  of  longitudinal  reddish  fibres,  which  admit  of  a  con- 
siderable degree  of  distention,  are  difficult  to  break,  as  was 
proved  by  the  experiments  of  Wintringham,  and  can  be 
distinguished  only  in  the  larger  veins  near  the  heart.  The 
middle  coat  appears  to  be  wanting  in  the  veins  within  the 
bones;  and  in  the  sinuses  of  the  brain,  its  place  is  supplied 
by  duplicatures  of  the  dura  mater.  Its  chemical  compo- 
sition shows  that  it  consists  principally  of  fibrin. 

Internal  coat. — The   internal  or  common  coat  is  thin, 
smooth,  and  polished,  of  a  filamentous  texture,  and  much 
more  extensible  and  resisting  than  that  of  the  arteries;  it  is 
a   mere   continuation   of  the  membrane  which  lines   the 
cavities  of  the   heart,    and   alone    constitutes   the   veins 
within  the  bones  and  the   sinuses  of  the  dura  mater.     On 
its  internal  surface  it  presents  a  great  number  of  paraboli- 
cal folds  that  are  called  valves,  whose  convex  edge  is  at- 
tached, and  presents  towards  the  origin  of  the  veins,  while 
the  other,  which  is  straight  or  slightly  concave,  is  directed 
towards  the  heart.     The  valves  are  applied  against  the  in- 
ternal surface  of  the  vein  by  the  motion  of  the  blood   that 
is  contained  in  its  canal:  whenever  there  is  a  retrograde 
motion  of  this  fluid,  it  escapes  between  the  membranous 
folds,  and  the  parietes  of  the  veins,  so  that  the  valves  be- 
come almost  perpendicular  to  the  vessel,  and  form  a  species 
of  bag,  whose  cavity,  being  directed  towards,  the  heart, 
receives  the  blood,    and  prevents  its  return.     They  are 
generally  large  enough  to  close  the  canal  of  the  vessel;  but 
sometimes  they  are  imperfect,  and  are  mere  projections, 
or  transverse  bands,  as  we  see  examples  in  the  femoral  vein 
and  in  the  sinuses  of  the  dura   mater.     Sometimes,   the 
veins  also  present  anomalies,  such  as  fissures,  on  their  free 
edges,   a  reticular  structure,  &c. — anomalies   which   are 
either  congenital,  or,  as  is  most  frequently  the  case,  a  con- 
sequence of  the  mechanical  action  of  the  blood.     They  are 
generally  found  in  pairs,  and  are  placed  oppositely  to  one 
another;  in  the  smaller  veins,  however,  they  are  single; 


or  THE  VEINS.  53 

and  sometimes,  instead  of  two,  there  are  three  or  four. 
The  existence  of  the  valves  is  generally  uniform,  but  in 
some  veins,  as  in  the  minute  ramifications,  and  the  great 
visceral  trunks,  they  are  entirely  wanting;  they  exist  chief- 
ly in  the  superficial  veins,  especially  in  those  of  the  extremi- 
ties, and  are  more  numerous  and  nearer  each  other  in  the 
small  than  in  the  large  veins.  They  are  generally  found  at 
the  junction  of  the  ramifications  with  the  branches,  and  of 
these  with  the  trunks.  The  valves  prevent  the  retrograde 
flow  of  the  blood,  facilitate  its  progress  towards  the  heart, 
and  are  chiefly  situated  in  those  parts  where  its  circulation 
is  most  difficult 

The  veins  receive  but  a  small  proportion  of  vasa  vaso- 
rum,  and  of  nerves,  and  these  are  principally  derived  from 
the  ganglia.  The  nerves  which  supply  the  pulmonary 
veins  are  chiefly  from  the  anterior  pulmonary  plexus. 

Characters  and  physical  properties. — The  veins  are  of 
a  whitish,  semi-transparent  colour,  very  extensible,  and 
susceptible  of  a  considerable  degree  of  dilatation;  they  are 
less  elastic  than  the  arteries,  and  their  parietes  have  not 
sufficient  firmness  to  retain  their  caliber,  when  empty, 
unless  they  adhere  by  their  external  surface  to  the  sur- 
rounding parts. 

Vital  properties. — The  veins  enjoy  but  an  inconsidera- 
ble degree  of  sensibility,  and  their  contractility  of  texture 
can  be  distinguished  only  in"  the  larger  trunks. 

Differences  according  to  age. — We  have  already  seen, 
that  the  capacity  of  the  venous  system  is  about  equal  to 
the  arterial  in  infancy,  but  it  is  greater  in  the  adult,  and 
still  more  so  in  old  age.  This  difference  shows,  that 
in  proportion  as  we  advance  from  the  cradle  to  the  grave, 
the  circulation  becomes  more  languid,  and  that  the  decay 
of  our  organs  exceeds  their  growth;  two  causes,  which  by 
accumulating  a  greater  quantity  of  blood  in  the  veins,  deter- 
mine their  dilatation  with  a  diminution  of  their  parietes. 
Ossification  and  depositions  of  earthy  phosphates,  so  com- 


54  OP  THE  VEINS. 

mon  in  the  coats  of  the  arteries,  seldom  take  place  in  those 
of  the  veins. 

Functions. — The  veins  bring  back  the  blood  to  the  au- 
ricles of  the  heart,  after  it  has  furnished  the  materials  of 
secretion  and  nutrition,  and  receive  the  fluids  which  have 
been  absorbed  by  the  lacteals  and  absorbents.  The  circula- 
tion of  the  veins  is  rendered  evident:  first,  by  the  pheno- 
mena which  attend  the  application  of  ligatures,  viz.  by  the 
obliteration  of  their  caliber  between  the  heart  and  the  liga- 
ture, and  their  distention  between  this  last  and  the  venous 
capillaries;  secondly,  by  the  direction  of  the  valves;  third- 
ly, by  microscopic  observations.  The  motion  of  the  blood 
in  the  veins  is  uniform  and  uninterrupted.  The  veins  pre- 
sent no  pulsations,  except  in  those  cases,  where  in  conse- 
quence of  impeded  respiration,  or  an  organic  affection  of 
the  heart,  the  contraction  of  the  right  auricle  causes  a  reflux 
of  a  portion  of  the  blood  into  the  vena;  cavse,  while  the  other 
passes  into  the  right  ventricle.*  The  motion  exerted  up- 
on the  parietes  of  the  veins  by  the  blood  thus  repelled, 
constitutes  the  venous  pulse,  which  can  be  distinguished 
only  in  the  great  branches,  near  the  heart.  The  circula- 
tion of  the  blood  in  the  veins  is  produced;  first,  by  the 
contraction  of  the  left  ventricle,  which  has  a  considerable 
influence  on  the  course  of  the  blood  in  the  veins;  secondly, 
by  the  specific  action  of  the  parietes  of  the  veins;  thirdly, 
by  the  contraction  of  the  surrounding  muscles;  fourthly, 
by  the  suction  of  the  blood  of  the  venas  cavas,  which  is  pro- 
duced by  the  dilatation  of  the  right  auricle  of  the  heart, 
and  is  more  remarkable,  when,  from  the  tendency  to  a  va- 
cuum, the  lungs  are  called  into  greater  action. t    Finally, 

*  This  reflux  also  takes  place  in  health,  especially  during  expiration, 
but  it  is  not  sufficient  to  be  appreciated  on  the  exterior  of  the  body. 

fDr.  Barry,  in  a  work  which  he  has  published  on  the  causes  of  the 
circulation  of  the  veins,  states  a  number  of  recent  experiments,  by 
which  he  tends  to  prove,  that  the  blood  traverses  the  veui3  only  during 
inspiration:  but  it  appears  to  us  that  he  has  exaggerated  the  influence 


OF  THE  VEINS.  55 

the  direction  of  the  valves  and  the  great  number  of  anasto- 
moses favour  the  circulation  of  the  blood  in  the  veins. — 
All  these  causes^  however,  are  by  no  means  capable  of  pro- 
ducing a  force  equal  to  that  which  the  arterial  blood  re- 
ceives from  the  action  of  the  heart,  and  are  not  sufficient 
completely  to  neutralize  the  laws  of  gravitation.* 

M.  Magendie  and  some  modern  physiologists  have  per- 
formed a  great  number  of  experiments  on  the  veins,  and 
have  clearly  and  satisfactorily  demonstrated  that  they  are 
absorbents.  This  opinion,  entertained  by  Galen  and  his 
successors  until  the  time  of  T.  Bartholine,  combined  with 
that  which  denies  to  the  lymphatic  vessels  any  other  office 
than  that  of  mere  absorbents  of  the  chyle,  will  be  more  ful- 
ly discussed  in  the  history%qf  the  lymphatic  system. 

Pathological  Anatomy. 

The  veins  are  frequently  subject  to  dilatations,  which  oc- 
cupy either  the  whole  or  only  a  part  of  their  circumference, 
and  constitute  what  are  termed  varices.  These  affections 
are  generally  produced  by  the  pressure  of  the  blood  against 
the  parietes  of  the  veins,  and  are  consequently  more  com- 
mon in  those  parts  where  the  blood  circulates  against  its 
own  gravity,  and  where  it  is  impeded  in  its  course,  as  in 
the  veins  of  the  inferior  extremities,  the  pelvis,  &c,  vari- 
cose veins  often  present  a  serpentine  direction,  which  in- 
dicates an  increase  not  only  of  their  caliber,  but  also  of  their 
length. — Instances  have  been  related  where  the  whole 
venous  system  was  in  a  varicose  state,  t 

which  inspiration  has  on  the  motion  of  the  blood,  in  regarding  it  as  its 
essential  cause,  and  as  the  cause  of  the  dilatation  of  the  auricles. 

*  According  to  M.  de  Blainville,  the  dilatory  progress  of  the  blood  in 
the  veins,  allows  the  elements  of  this  fluid  a  longer  time  to  favour  the 
modifications  which  they  undergo  by  their  mutual  reaction;  modifica- 
tions, which  are  not,  as  has  been  hitherto  supposed,  the  result  of  an 
organic  action  of  the  parietes  of  the  vessels. 

f  Puchelt,  author  of  a  German  work  on  the  diseases  of  the  veins, 


56  OF  THE  VEINS. 

The  aneurismal  varix  is  a  tumour,  arising  from  a  pre- 
ternatural and  direct  communication  between  a  vein  and 
an  artery.  It  is  generally  caused  by  wounds  or  by  the  ulce- 
ration of  the  contiguous  parietes  of  the  two  vessels.  When 
a  consecutive  false  aneurism  is  formed  in  the  intermediate 
tissue  between  two  injured  vessels,  it  is  termed  varicose 
aneurism. 

Morbid  contractions  of  the  veins  are  more  uncommon 
than  dilatations,  but  when  they  do  occur,  they  depend  most 
frequently,  either  on  an  obstruction  of  the  circulation,  or 
a  chronic  inflammation,  which  produces  a  thickening  of 
their  parietes,  or  an  effusion  of  a  plastic  and  membraniform 
matter,  which  lines  their  internal  surface.  In  some  instan- 
ces the  venae  cavae  and  the  jugular  veins  are  thus  complete- 
ly obliterated,  without  causing  an  interruption  of  the  cir- 
culation. This  alteration  may  be  either  general  or  local. 
Wounds  of  the  veins  heal  more  readily  than  those  of 
the  arteries;  and  their  cicatrization,  though  not  imme- 
diate, is  produced  by  an  effusion  of  coagulating  lymph, 
which  closes  up  the  lips  of  the  wound.  When  a  vein 
has  been  completely  divided,  the  two  extremities  retract, 
like  those  of  an  artery,  but  the  coagulum  which  closes 
up  their  caliber  is  smaller,  and  the  part  of  the  vessel  which 
has  ceased  to  perform  its  functions,  is  obliterated  and  con- 
verted into  a  cord.  Wounds  of  the  veins  are  more  frequent- 
ly followed  by  inflammation  and  ulceration  than  the  arteries. 
Ligatures  applied  around  them  divide  the  internal  coat 
only  secondarily,  and  through  the  medium  of  the  inflam- 
mation which  they  create. 

Phlebitis  or  inflammation  of  the  veins  is  a  frequent  dis- 
ease, and  generally  arises  from  one  of  the  following  causes; 
1st,  from  wounds  of  the  veins;  2d,  from  the  application 
of  ligatures;  3d,  from  inflammation  of  the  surrounding  tis- 

strongly  insists  upon  this  general  dilatation,  which,   according-  to  him, 
constitutes  an  important  character  in  many  diseases. 


OF  THE  LYMPHATIC  VESSELS.  57 

sues;  4th,  from  a  varicose  state  of  these  vessels.  The  anato- 
mical characters  of  inflammation,  are,  a  considerable  de- 
gree of  redness  of  the  internal  membrane,  accompanied  by 
a  thickening  of  the  other  coats;  by  collections  of  purulent 
matter  on  the  external  surface  of  the  vein,  and  an  effusion 
of  coagulating  lymph  on  its  interior.  Inflammation  of  the 
veins  generally  travels  in  the  direction  of  the  heart,  and 
sometimes  even  extends  as  far  as  that  organ,  and  destroys 
the  life  of  the  patient.  The  parietes  of  the  veins  seldom 
ossify,  but  sometimes  there  are  small  inorganic  concre- 
tions, of  the  size  of  a  millet  seed,  or  a  small  pea,  which 
occur  more  particularly  in  the  veins  of  the  pelvis,  and  in 
those  where  the  course  of  the  blood  is  most  difficult.  These 
productions,  called  phlebolithes,  sometimes  adhere  to  the 
internal  surface  of  the  veins,  are  commonly  situated  in  the 
dilatations  of  these  vessels,  and  are  covered  by  a  very  thin 
membrane.  They  consist  of  several  layers,  and  often  ap- 
pear to  be  fibrous. 


section  v. 

Of  the  Lymphatic  System. 

1.  of  the  lymphatic  vessels. 

Definition. — The  lymphatics  are  small  transparent  ves- 
sels, which  originate  in  every  part  of  the  body,  and  unite 
to  form  several  trunks,  which  terminate  in  the  general 
venous  system. 

The  lymphatics  which  arise  on  the  surface  of  the  intes- 
tines are  denominated  the  lacteal  or  chyliferous  vessels, 
while  those  which  originate  in  the  substance  of  the  organs 
are  called  the  true  lymphatic  vessels. 

General  conformation. — The  lymphatic  system  pre- 
sents rather  a  reticular  than  arborescent  arrangement,  and 
consists  of  a  multitude  of  vessels  which  communicate  with 
9 


58  OF  THE  LYMPHATIC  VESSELS. 

each  other  by  numerous  ramifications,  and  terminate  in 
two  principal  trunks. 

Situation. — All  the  organs,  with  the  exception  of  the 
brain,  the  spinal  marrow,  the  eye,  the  internal  ear,  and  the 
placenta,  contain  lymphatic  vessels.  Like  the  veins,  they 
are  distributed  in  superficial  and  deep  seated: — this  arrange- 
ment exists  not  only  in  the  extremities  and  in  the  parietes 
of  the  visceral  cavities,  but  also  in  the  organs  that  are  con- 
tained within  these  last. 

Volume. — The  volume  of  the  lymphatic  vessels  is  smaller 
than  that  of  the  veins;  but  in  this  respect  they  present  less 
difference  between  their  ramifications  and  branches,  and 
remain  small,  notwithstanding  their  successive  union.  The 
lymphatic  vessels  of  the  head  are  the  smallest  in  the  body; 
those  of  the  superior  extremities  are  a  little  larger;  while 
those  of  the  trunk  and  the  inferior  extremities  are  the  most 
voluminous.  Number  and  capacity. — The  number  of 
these  vessels  is  much  greater  than  that  of  the  veins,  there 
being  on  an  average  ten  lymphatics  to  a  venous  or  arterial 
trunk;  which  accounts  for  the  fact  that  their  united  capaci- 
ty is  equal  to  that  of  the  venous  system,  notwithstanding 
the  exiguity  of  their  volume.  Form. — The  form  of  the 
lymphatic  vessels  is  that  of  small  tubes  intersected  by  nu- 
merous nodosities,  which  correspond  to  the  valves  on  their 
internal  surface. 

Origin. — The  origin  of  the  lymphatic  vessels  has  hitherto 
eluded  all  our  researches;  and  all  the  knowledge  we  possess 
upon  this  point,  is  involved  in  the  mazes  of  hypotheses. 
The  continuity  of  their  roots  with  the  arterial  capillaries  is 
still  doubtful,  and  has  been  proved  only  by  the  single  fact 
that  matter  of  injection  has  sometimes  been  found  to  pene- 
trate from  the  arteries  into  the  lymphatics.  This  pheno- 
menon, attested  only  by  a  small  number  of  experiments, 
does  seldom  take  place  unless  there  be  a  rupture  of  the 
small  arteries.  Be  this  as  it  may,  it  is  certain  that  the  lym- 
phatic vessels  arise  in  the  interior  of  the  organs,  and,  ac- 


OF  THE  LYMPHATIC  VESSELS.  59 

cording  to  some  anatomists,  on  the  surface  of  the  tegumen- 
tary  and  serous  membranes.  The  most  delicate  lymphatic 
roots  that  can  be  discovered,  anastomose  so  frequently  with 
each  other,  as  to  form  complete  meshes,  sufficiently  com- 
pact to  constitute  the  basis  of  some  of  the  organs,  such  as 
the  serous  and  tegumentary  membranes,  &c.  Their  larger 
branches  communicate  together  at  more  considerable  dis- 
tances, yet  their  anastomoses  are  always  more  numerous 
than  those  of  the  veins,  and  present  every  where  a  reticu- 
lar arrangement.  Course. — On  the  course  of  these  vessels 
are  found  every  where  the  absorbent  or  lymphatic  glands, 
which  are  entered  on  the  side  remote  from  the  thoracic 
duct  by  numerous  ramifications  of  the  absorbent  vessels, 
termed  vasa  inferentia;  which  escape  on  the  near  side  by 
a  smaller  number,  termed  vasa  efferentia.  Most  of  the 
lymphatic  vessels  pass  in  this  manner  through  several 
glands,  especially  those  of  the  mesentery,  where  these 
glands  are  more  numerous  than  any  where  else;  while  those 
of  the  extremities  run  a  considerable  distance,  and  even 
several  feet,  without  meeting  them.  Termination. — The 
lymphatic  vessels  terminate  in  two  principal  trunks;  the 
one,  termed  the  thoracic  duct,  commences  at  the  reservoir 
of  Pecquettii,  opposite  to  the  second  lumbar  vertebra,  and 
terminates  in  the  left  subclavian  vein,  after  having  received 
the  lymphatic  vessels  of  the  inferior  extremities,  the  ab- 
domen, a  great  part  of  the  thorax,  the  superior  left  ex- 
tremity, and  of  the  left  lateral  half  of  the  head  and  neck. 
The  other,  termed  the  vena  lymphalica  dextra,  is  formed 
by  the  union  of  the  lymphatic  vessels  of  the  superior  right 
extremity,  by  a  part  of  the  chest,  and  the  right  lateral  half 
of  the  head  and  neck;  and  terminates,  after  a  very  short 
course,  in  the  right  subclavian  vein.*    A  great  number  of 

*  An  anatomist  of  Florence,  Doctor  Rigolo  Lippi,  has  lately  discover- 
ed several  other  lymphatic  trunks  of  a  large  size,  and  three  smaller  ones, 
terminating  in  the  vena  cava  inferior,  near  the  third  lumbar  vertebra;  a 


GO  OF  THE  LYMPHATIC  VESSELS. 

the  lymphatics  terminate  directly  in  the  neighbouring 
veins.  This  fact,  well  known  at  the  present  day,  accounts 
for  the  rapidity  with  which  substances  that  have  been  ab- 
sorbed, enter  the  circulation. 

Surfaces. — The  external  surface  of  the  lymphatics  is 
uneven,  and  adherent  to  the  surrounding  parts;  the  interval 
is  smooth  and  furnished  with  a  great  number  of  valves. 

Structure. — The  parietes  of  the  lymphatic  vessels  are 
composed  of  two  membranous  layers,  and  of  the  cellular 
sheath  common  to  all  the  vessels.  The  external  membrane 
is  strong  and  firm,  and  from  its  filamentous  texture,  has 
been  supposed  to  consist  of  muscular  fibres;  the  internal  is 
extremely  thin  and  brittle,  and  forms  the  numerous  valves 
which  are  found  on  the  interior  of  the  lymphatic  vessels. 
These  folds  are  arranged,  as  in  the  veins,  either  in  pairs, 
or  single,  and  are  generally  of  a  parabolical  form,  but  in 
some  of  the  lymphatics,  as  in  those  of  the  liver,  they  are 
annular.  They  are  very  numerous  in  the  branches,  and 
still  more  so  in  the  ramifications,  while  there  are  but  few 
in  the  trunks. — There  is  a  pair  of  these  valves  at  the  union 
of  the  lymphatic  trunks  with  the  subclavian  veins,  to  pre- 
vent the  regurgitation  of  their  contents. — The  parietes  of 
the  lymphatic  vessels  are  supplied  with  arteries,  veins,  and 
lymphatics,  but  no  nerves  have  as  yet  been  discovered  in 
them. 

Physical  properties. — In  proportion  to  the  thickness  of 
their  parietes,  the  lymphatic  vessels  have  more  resistance 
than  the  arteries  and  the  veins. — They  enjoy  a  great  de- 
gree of  extensibility,  and  are  susceptible  of  retraction  after 
death; — a  fact  which  proves  their  elasticity.  On  these  pro- 
perties depend  the  astonishing  variations  of  volume  of  the 
lymphatics,  accordingly  as  they  are  full  or  empty. 

Vital  properties. — The  vital  contractility  of  the  lym- 

fourth  terminates  in  the  primitive  iliac,  and  some  others,  which  are  dis- 
tributed to  the  renal  veins. 


OF  THE  LYMPHATIC  VESSELS.  61 

phatic  vessels  is  sufficiently  evident;  but  their  sensibility 
is  so  obscure  that  it  can  be  distinguished  only  when  they 
are  in  a  state  of  inflammation. 

Differences  according  to  age. — Our  knowledge  of  the 
lymphatic  system  is  too  limited  to  enable  us  to  say  any 
thing  decisive  with  regard  to  the  varieties  of  form,  capa- 
city, &c,  of  these  vessels,  in  the  different  periods  of  life. 
Pathological  observations  would  induce  us  to  believe  that 
they  are  more  fully  developed,  and  enjoy  a  greater  share 
of  vital  energy  in  infancy  and  youth  than  at  any  other  pe- 
riods of  life. 

Functions. — The  office  of  the  lymphatic  vessels  is  to 
take  up  in  every  part  of  the  body,  and  on  the  surfaces  of 
all  the  membranes,  the  substances  which  enter  the  circula- 
tion;— to  furnish  the  blood  with  the  chyle  and  lymph,  to 
convey  them  to  the  thoracic  duct,  and  evacuate  them  in  the 
venous  system.  As  some  of  these  functions,  however, 
have  been  denied  to  the  lymphatic  vessels,  we  shall  here 
enter  into  a  brief  detail  of  some  of  the  facts  that  have  been 
advanced  in  favour  of  their  absorbent  powers,  as  well  as 
some  of  those  of  an  opposite  character. 

The  ancients,  who  were  entirely  ignorant  of  the  existence 
of  the  lymphatic  vessels,  regarded  the  veins  as  the  sole 
agents  of  absorption.  This  opinion  prevailed  until  the 
time  of  Hunter  and  Cruikshank,  who  ascribed  the  power 
of  absorption  to  the  lymphatics,  which,  from  that  period, 
received  the  name  of  absorbent  vessels,  and  retained  it  ex- 
clusively until  1809.  At  this  period  M.  Magendie,  the 
celebrated  French  physiologist,  published  several  experi- 
ments which  tended  to  prove:  1st,  that  an  animal  would 
survive  several  days  after  the  thoracic  duct  was  secured 
by  means  of  a  ligature;  2d,  that  it  would  neither  accele- 
rate nor  retard  the  effects  of, poison;  3d,  that  poison  ex- 
posed to  a  surface  which  communicated  with  the  rest  of 
the  body  only  by  an  artery  and  a  vein,  would  prove  equal- 
ly fatal  to  the  animal  economy;  4th,  that  colouring  and 


62  OF  THE  LYMPHATIC  VESSELS. 

odorous  substances  could  be  detected  in  a  very  short  time 
in  the  veins,  but  not  in  the  lymphatic  vessels.  From 
these  facts  M.  Magendie  concluded,  that  the  veins  possess 
the  faculty  of  absorption,  that  the  chyliferous  vessels 
absorb  chyle  only,  and  that  the  rest  of  the  lymphatic 
system  is  devoid  of  this  function.  This  manner  of  ex- 
plaining absorption  was  adopted  by  the  most  celebrated 
German  physiologists,  who,  with  M.  Ribes  repeated  and 
modified  the  experiments  of  Magendie.  The  researches 
of  M.  Ribes  led  him  to  suppose  that  a  certain  propor- 
tion of  the  veins  commence  in  open  mouths,  or  in  the 
pores  of  the  laminous  tissues  of  the  organs,  and  that  he 
saw  traces  of  pus  and  fat  in  the  venous  system,  while  he 
searched  for  them  in  vain  in  the  lymphatic  vessels.  In  the 
further  investigation  of  this  subject,  M.  Segalas  submitted 
poisonous  substances  to  the  action  of  a  portion  of  intestine, 
having  previously  insulated  it,  and  carefully  secured  its 
vessels,  with  the  exception  of  an  artery  and  a  correspond- 
ing vein,  which  were  left  uninterrupted  to  preserve  the 
life  of  the  part:  the  presence  of  the  poison  was  not  evinced 
in  the  system,  nor  did  it  prove  fatal  to  the  animal  until 
after  another  vein  was  untied.  All  these  experiments,  and 
others  of  nearly  a  similar  nature  and  with  the  same  results, 
gave  rise  to  the  opinion,  adopted  by  a  great  number  of  phy- 
siologists of  the  present  day,  that  the  veins  are  the  sole 
agents  of  absorption.  The  discovery  of  Mr.  Fohmann, 
an  anatomist  of  Heidelberg,  of  a  communication  of  the 
lymphatic  vessels  with  the  veins,  and  of  a  great  number  of 
lymphatics  in  the  lymphatic  glands,  and  in  the  substance 
of  the  organs,  appears  to  be  sufficient  to  account  for  the  re- 
sults of  the  preceding  experiments.  The  important  dis- 
covery of  Dr.  Lippi,  and  the  researches  of  Mr.  Lauth  ju- 
nior, concur  to  support  the  observations  of  Fohmann. 
Mr.  Lauth  asserts,  that  the  veins  are  continuous  with  the 
arteries,  and  that  they  do  not,  as  has  been  supposed  by 
some,  originate  in  open  mouths,  and  also  that  they  are  des- 


OF  THE  LYMPHATIC  GANGLIA.  63 

titute  of  inorganic  pores;  whence  he  concludes,  that  the 
lymphatics  possess  the  faculty  of  absorption,  and  that  there 
is  no  proof  that  the  veins  perform  this  function,  since 
foreign  substances,  found  in  the  blood,  are  carried  directly 
to  the  circulation,  their  elimination  being  hastened  by  the 
numerous  lymphatic  branches  which  communicate  with 
the  veins  in  the  interior  of  the  lymphatic  glands,  and  in 
other  parts  of  the  system. 

Such  is  the  present  state  of  our  knowledge  with  regard 
to  the  true  agents  of  absorption.  No  doubt  this  faculty 
does  not  belong  exclusively  to  the  lymphatics  and  the  veins, 
since  it  takes  place  to  a  greater  or  less  extent  in  all  the 
tissues  of  the  body. 

2.    OP  THE  LYMPHATIC  GANGLIA. 

Definition. — The  conglobate  glands  or  lymphatic  gan- 
glia, are  small  oval  bodies,  situated  on  the  course  of  the 
lymphatic  vessels. 

Form  and  volume. — These  ganglia  are  more  round  and 
globular  in  proportion  as  their  volume  is  smaller,  and  more 
flattened  and  elongated  in  proportion  as  it  is  more  consi- 
derable. Their  size  varies  from  a  lentil  to  that  of  an  al- 
mond. 

Situation. — The  lymphatic  ganglia  are  found  chiefly  in 
the  neighbourhood  of  the  great  joints,  especially  in  the  arm- 
pits, the  groins,  &c.  but  they  are  still  more  numerous  in 
the  thoracic  and  abdominal  cavities,  and,  in  general,  in  the 
vicinity  of  the  lymphatic  trunks  and  the  surface  by  which 
new  substances  are  introduced  into  the  animal  economy. 

Structure.  —These  glands  appear  to  consist  of  a  soft, 
fleshy,  porous  substance,  contained  in  a  membranous  cap- 
sule, which  is  derived  from  the  condensation  of  the  cellu- 
lar tissue  in  which  they  are  embedded:  they  are  essentially 
composed  of  the  vasa  inferentia,  of  blood  vessels  which 
anastomose  with  them,  and  of  filaments  of  nerves. 


64  OP  THE  LYMPnATIC  GANGLIA. 

Physical  characters. — The  lymphatic  ganglia  are  firm 
and  resisting,  and  vary  in  colour  in  the  different  regions  in 
which  they  are  found.  They  are  of  a  yellowish  tint  in 
the  neighbourhood  of  the  liver,  white  in  the  mesentery, 
and  of  a  dark  brown  colour  around  the  bronchia  and  the 
spleen. 

Vital  properties. — The  vital  properties  of  these  glands 
are  too  obscure  to  be  appreciated  in  the  healthy  state. 

Differences  according  to  age. — The  lymphatic  ganglia 
are  larger,  more  soft,  and  of  a  deeper  colour,  and  enjoy  a 
greater  degree  of  vital  energy  in  infancy  than  in  the  sub- 
sequent periods  of  life.  In  old  age,  they  sometimes  waste 
to  such  a  degree,  as  almost  entirely  to  disappear. 

Functions. — The  lymphatic  and  lacteal  vessels  all  pass 
through  these  glands,  by  which  the  lymph  and  chyle  are 
supposed  to  undergo  certain  changes,  and  to  begin  to  be 
mixed  with  the  blood.  They  are  probably  also  of  use  in 
entangling  noxious  and  acrid  particles,  and  in  preventing 
them  from  entering  the  circulation. 

Pathological  Jlnatomy. 

Congenital  anomalies  are  frequently  met  with  in  the 
lymphatic  system;  thus  the  thoracic  duct  is  sometimes 
double,  or  it  splits  into  two  branches,  one  of  which  enters' 
the  subclavian  vein,  and  the  other  the  internal  jugular. 
The  lymphatics,  like  the  veins,  are  subject  to  dilatations, 
which  are  produced  by  mechanical  causes,  and  are  termed 
cirsus.  Sometimes  we  see  a  portion  of  a  lymphatic  vessel 
filled  with  a  number  of  small  vesicles  which  have  been 
considered  as  hydatids  by  some  authors,  and  have  been  re- 
ferred to  alternate  enlargements  and  contractions  between 
the  intervals  of  some  of  the  valves.  The  lymphatic  system 
is  often  affected  with  inflammation,  which  is  generally  slow 
in  its  progress,  and  gives  rise  to  various  morbid  pheno- 
mena which  may  be  attributed  to  a  scrofulous  diathesis. 
It  may  terminate  in  suppuration,  the  effusion  of  albumin- 


BIBLIOGRAPHY  OF  THE  VASCULAR  SYSTEM.  65 

ous  matter,  or  in  the  obliteration  of  the  parietes  of  the 
vessel. 

The  lymphatic  ganglia  also,  present  many  varieties  both 
as  regards  their  form  and  situation:  they  are  subject  to  in- 
flammation, to  schirrous,  carcinomatous  and  tubercular  af- 
fections. Ossification,. or  the  deposition  of  earthy  matter, 
is  more  frequent  in  these  glands  than  in  the.  lymphatic  ves- 
sels, and  may  be  observed  to  occur  sometimes  even  at  a 
very  early  age.  Inflammation  of  these  glands  terminates 
more  frequently  in  induration  than  in  any  other  tissue. 

Bibliography  of  the  Vascular  System. 

The  treatises  on  general  and  pathological  anatomy  al- 
ready cited. 
1°.  Arteries. 

Haller.  Oper.  minor.,  torn.  I,  page  60—241. 

Rolando.  Memoire  sur  la  formation  du  Coeur  et  des  Vais- 
seaux  arteriels  veineux  et  capillaires:  insere  dans  le  Jour- 
nal compl6mentaire  du  Dictionnaire  des  Sciences  m6di- 
cales,  torn.  XII,  page  34. 

Corvisart.  Essai  sur  les  maladies  du  Coeur  et  des  gros 
vaisseux.  Paris,  1806. 

Hodgson.  Maladies  des  Arteres  et  des  Veines,  trad,  par 
M.  Breschet.  Paris,  1809.  , 

Berlin.  Traite  des  maladies  du  Coeur  et  des  gros  vaisseaux, 
redige  par  J.  Bouillaud.  Paris,  1824. 

D.  Belmas.  Structure  des  Arteres,  leurs  proprietes,  leurs 
fonctions  et  leurs  alterations  organiques.  in  4o.  Stras- 
bourg, 1822. 

Fr.  Tiedemann.  Tabulae  Arteriarum  corporis  humani. 
Carlsruhse,  1822. 

Scarpa.  M6moire  sur  l'Anevrysme,  traduit  par  M.  Del- 
pech.  Paris,  1809. 

Jl.  Biclard.  Sur  les  blessures  des  Arteres,  Memoires  de  la 

Soci6t6  medicale  d'Emulation,  torn.  VIII,  Paris,  1817. 

Voy.  sur  la  ligature  de  1'aorte  les  CEuvres  chirurgicales 
10 


66  BIBLIOGRAPHY  OF  THE  VASCULAR  SYSTEM. 

de  Jf.  Cooper  et  B.  Travers,  traduites  de  l'anglais,  2  vol. 
in  80.  Paris,  1S23. 
2°.    Capillaries. 
Malpighi.  Epist.  II,  in  oper.  omn. 
Leuwenhoeck.  Exper.  et  contempl.  arcan.  natur.  detect. 

epist.  65 — 67. 
Spallanzani.  Experiences  sur  la  circulation,  p.  255.  Trad. 

de  l'italien  par  J.  Tourdes.   In  80.  Paris,  an  S. 
Proschaska.  De  vasis  sanguin.  capill.  in  disquisit.  anat. 
physiol.  organismi  corp.  hum.  Viennae,  1812. 
3°.    Veins. 

We  possess  no  special  information  on  the  anatomy  of 
the  veins,  considered  in  their  healthy  state,  but  what  is 
found  in  the  treatises  of  general  anatomy.    On  the  diseases 
of  the  veins  consult  the  following  memoirs: — 
M.  J.  Bouillaud.  Recherches  cliniques  pour  servir  a  l'his- 
toire  de  la  Phlebite,  etc. ,  deuxieme  article,  Caracteres 
anatomiques,  dans  la  Revue  medicale,  juin  1825. 
M.  F.  Ribes.  Expose  succinct  des  Recherches  sur  la  Phl6- 
bite,  meme  recueil,  juillet  1825,  et  Memoires  de  la  So- 
ciete  medicale  d'Emulation,  torn.  VIII,  1816. 
M.  J.  Bouillaud.  De  l'obliteration  des  veines  et  de  son  in- 
fluence sur  la  formation  des  hydropisies  partielles,  dans 
les  Arch,  gener.  de  Med.,  juin  1823,  pag.   188,  et  mai 
1824,  pag.  194. 
4°.   Lymphatics. 
Cruikshank.  Anatomie  des  Vaisseaux  absorbans,  trad,  de 

l'anglais  par  Petit-Radel.  Paris,  1787. 
Lauth  fils.  Essai  sur  les  vaisseaux  lymphatiques.  Stras- 
bourg, 1824. 

The  persons  who  are  desirous  of  having  a  knowledge  of 
the  recent  works  on  the  organs  of  absorption,  will  find  the 
greater  part  in  the  following  memoirs: — Magendie,  Me- 
moire  sur  les  organes  de  l'absorption  chezles  Mammiferes 
(Journ.  de  Physiol,  exper.,  torn.  I,  p.  18,) — Voy.  aussi  son 
Precis  61em.  de  physiol.,  torn.  II,  pag.  179,  192  et  257. 


BIBLIOGRAPHY  OF  THE  VASCULAR  SYSTEM.  67 

2e.  edit.  Paris,  1825. — Segalas.  Note  sur  Pabsorption  in- 
testinale.  (Recueil  precite,  torn.  II,  page  11.) — Ribes. 
Mem.  de  la  Soc.  med.  d'Emul.,  18' 7,  torn.  VIII,  p.  604 
et  suiv.  —  Tiedemann  et  Gmelin,  Recherches  sur  la  route 
que  prennent  diverses  substances  pour  passer  de  l'estomac 
et  du  canal  intestinal  dans  le  sang,  trad,  de  l'allemand. 
Paris,  1821. — Fodera,  Recherches  experimentales  sur  l'ab- 
sorption  et  l'exhalation.  Paris,  1824.  —  Vertrumb,  Mem. 
ins.  dans  le  Journal  complementaire  du  Dictionnaire  des 
Sciences  m6dicales,  torn.  XVI,  page  225,  Seller  et  Ficinus, 
Experiences  sur  le  pouvoir  absorbant  des  veines,  meme 
recueil,  tome  XVIII,  p.  318,  et  tome  XIX,  p.  125. 
Mard.  De  ^inflammation  des  vaisseaux  absorbans  lympha- 

tiques,  dermo'ides  et  sous-cutanes,  2e.  edit.  Paris,  1824. 
S.  Th.  Soemmering.  De  morbis  vasorum  absorb,  corp.  hum., 

in  So.  Traj.  ad  Mcen.  1795. 


68  OF  THE  SEROUS  SYSTEM. 


CHAPTER  III. 

OF  THE  SEROUS  SYSTEM. 

SECTION  1. 

General  Observations. 
Synonyma:  Simple  villous  membranes,  diaphanous  membranes,  &c. 

Definition. — The  serous  system  consists  of  an  assem- 
blage of  cystiform  membranous  organs,  insulated  from  each 
other,  and  presenting  two  surfaces;  one  of  which  is  free, 
every  where  contiguous  to  itself  and  continually  moistened 
by  the  exhalation  of  a  fluid,  which  resembles  the  serum  of 
the  blood;  the  other  rough  and  adherent  to  the  surround- 
ing parts. 

Division. — The  serous  system  is  divided  into  two  parts, 
the  splanchnic  and  the  synovial;  the  first  comprehends  the 
tunica  vaginalis  testis  and  the  serous  membranes  contain- 
ed in  the  visceral  cavities;  the  other  the  synovial  mem- 
branes of  the  joints,  the  bursse  mucosae,  &c. 

Conformation. — The  different  membranes  of  which  the 
serous  system  is  composed,  represent  shut  sacs,  which  may 
be  compared,  according  to  Bichat,  to  "  those  night  caps 
which  are  folded  within  themselves, "  The  peritoneum, 
however,  differs  somewhat  from  this  characteristic  confor- 
mation of  the  serous  membranes.  The  fallopian  tubes 
penetrate  into  its  cavity~,  and  furnish  by  this  arrangement 
the  only  example  of  continuity  between  the  serous  and 
mucous  membranes. 


OF  THE  SEROUS  SYSTEM.  69 

Surfaces. — The  serous  membranes  adhere  by  their  ex- 
ternal surface  to  the  surrounding  parts,  very  intimately  in 
some  places,  and  very  loosely  in  others.  Thus  it  is  extreme- 
ly difficult  to  separate  them  from  the  lungs,  the  spleen  and 
the  testicles,  as  well  as  from  the  articular  surfaces,  except 
where  they  begin  to  be  folded  on  themselves.  The  first 
may  also  be  very  readily  separated  from  the  subjacent 
parts  in  the  neighbourhood  where  they  pass  from  one  or- 
gan to  another.  The  external  surface  is  somewhat  rough, 
rugose,  and  covered  by  a  layer  of  cellular  tissue,  whose 
density  varies  in  the  different  parts  of  the  same  membrane. 
This  surface  constitutes,  by  its  reflections,  numerous  folds, 
of  which  the  omentum  and  the  mesentery  are  well  marked 
examples. 

The  internal  surface,  every  where  contiguous  to  itself, 
is  smooth  and  shining,  continually  moistened  by  a  serous 
exhalation,  and  presenting  numerous  villi,  which  can  be 
distinguished  only  with  the  aid  of  the  microscope. 

Texture. — The  serous  membranes  are  formed  of  a  sin- 
gle layer,  whose  texture  is  more  compact  in  proportion  as 
it  is  examined  near  their  free  surface.  Their  tissue  may 
be  regarded  as  a  modification  of  the  cellular;  indeed,  when 
a  portion  of  serous  membrane  is  powerfully  distended,  we 
may  perceive  a  great  number  of  layers  and  filaments,  which 
are  irregularly  interwoven  with  each  other.  Besides,  when 
the  serous  membranes  are  inflamed  they  become  red,  a 
character  which  belongs  also  to  the  cellular  tissue.  This, 
as  well  as  the  first,  is  the  seat  of  a  serous  exhalation,  whose 
properties  are  nearly  of  the  same  nature.  Add  to  this  that 
accidental  serous  membranes  (cysts)  are  sometimes  formed 
in  the  cellular  tissue  by  its  simple  condensation;  that,  ex- 
posed to  putrefaction,  both  tissues  resist  for  a  long  time  its 
action,  and  that  their  maceration  is  equally  slow  and  tedi- 
ous. Most  authors  regard  the  serous  membranes  as  being 
very  abundantly  supplied  with  pellucid  vessels,  which  do 
not  carry  red  blood  in  their  healthy  state;  while  Rudolph i 


70  OF  THE  SEROUS  SYSTEM. 

and  Ribes,  relying  upon  the  results  of  the  most  minute  dis- 
sections, assert  that  the  serous  membranes  are  destitute  of 
every  kind  of  vascularity. 

Characters,  physical  and  chemical  properties. — The 
serous  membranes  are  white  and  transparent,  and  enjoy 
some  degree  of  elasticity,  which  is  chiefly  appreciable  by 
the  facility  with  which  they  recover  their  original  state, 
after  they  have  been  considerably  distended.  Although 
very  extensible,  they  are  not  so  much  so,  as  the  enormous 
distention  of  which  they  are  capable  in  certain  dropsies, 
would  induce  us  to  believe.  It  ought  not  to  be  forgotten 
also,  that  the  folds  which  these  membranes  present  in  their 
healthy  state,  are  effaced  by  these  diseases,  and  that  they 
are  susceptible  of  considerable  displacement,  when  the 
cause  of  distention  operates  only  on  a  portion  of  their  ex- 
tent. Maceration  renders  them  opake;  desication,  on  the 
contrary,  increases  their  transparency.  Subjected  for  a 
long  time  to  the  action  of  ebullition,  they  furnish  gelatine 
and  albumen. 

Vital  properties. — In  their  healthy  state,  the  serous 
membranes  are  destitute  of  sensibility,  and  that  which  is 
observed  when  they  are  inflamed,  probably  belongs  to  the 
subjacent  tissues.  Their  nutrition  supposes  that  they  are 
possessed  of  some  degree  of  vitality,  inappreciable  in  any 
other  manner. 

Differences  according  to  age. — The  serous  system  is 
extremely  delicate  in  the  fcetus:  the  arachnoid  membrane 
and  the  omentum,  which  remain  the  most  thin  and  delicate 
through  life,  have,  in  the  foetus,  scarcely  the  thickness  of  the 
parietes  of  a  soap-bubble.  The  density  of  these  mem- 
branes increases  with  the  age  of  the  individual,  and  is  in 
an  inverse  ratio  with  its  elasticity.  In  old  age,  the  adhe- 
sions of  these  organs  become  stronger  and  more  resisting, 
while  in  infancy  they  are  loose  and  feeble.  The  serous 
membranes  accommodate  themselves  to  all  the  changes  of 


OF  THE  SEROUS  SYSTEM.  71 

form,  and  the  normal  displacements  of  the  organs  upon 
which  they  are  spread. 

Functions. — The  serous  membranes  serve  to  line  the 
visceral  organs,  and  to  insulate  them  from  each  other. 
This  insulation  is  rendered  more  complete  by  the  presence 
of  the  serum  which  lubricates  their  free  surface,  and  which 
serves  to  facilitate  the  motions,  and  prevent  adhesions  of 
the  contiguous  parts.  As  to  the  separation  of  this  fluid, 
Ruisch  has  demonstrated,  that  it  is  not  derived  from  a 
glandular  elaboration,  as  was  supposed  by  many  before  his 
time.  At  the  present  day  most  physiologists  are  of  opinion 
that  it  is  a  perspiratory  secretion,  an  organic  action  of  the 
serous  tissue,  or  only  of  the  vessels  which  are  distributed 
in  its  texture:  some  very  distinguished  physiologists,  how- 
ever, suppose  that  this  texture  performs  no  other  part  of 
the  exhalation  of  which  we  are  treating,  than  that  of  a  hy- 
grometric  substance.*  The  nature  and  quality  of  this  per- 
spiration vary  in  the  different  kinds  of  serous  membranes; 
it  re-enters  the  circulation  in  proportion  as  it  is  exhaled, 
and  undergoes  probably,  during  this  double  process,  a  modi- 
fication which  renders  it  more  fit  for  nutrition.  Bichat, 
in  demonstrating  that  the  extent  of  the  serous  surfaces,  in- 
dependently of  the  synovial  membranes,  was  equal  to  the 
tegumentary  membranes,  showed  the  great  importance  of 
the  serous  exhalations  and  absorptions. 

Pathological  Anatomy. 

The  serous  membranes  are  sometimes  thickened  at  the 
same  time  that  their  extent  is  increased.  This  phenome- 
non, which  is  often  observed  in  hernias  and  dropsies,  re- 
sults from  a  hypernutrition  (sarcroit.)  The  solutions  of 
continuity  of  these  organs  are  followed  by  a  linear  cicatrix, 

*  Rudolphi,  who  denies  every  kind  of  vascularity  to  this  system,  thinks 
that  the  serous  exhalation  is  derived  from  the  subjacent  vessels,  and 
that  it  traverses  the  serous  membranes  to  arrive  at  their  free  surface,  in 
the  same  manner  as  the  cutaneous  perspiration  traverses  the  epidermis. 


12  OF  THE  SEROUS  SYSTEM. 

which  is  almost  imperceptible  when  the  reunion  has  been 
immediate,  and  by  the  formation  of  a  new  portion  of  serous 
membrane,  when  immediate  reunion  has  not  been  effect- 
ed: this  portion  remains  always  more  thin,  and  more  ex- 
tensible than  the  rest  of  the  membrane.  The  first  effect  of 
inflammation  of  the  serous  membranes  is  a  suspension  of 
the  serous  exhalation,  which  soon  after  increases,  and  be- 
comes altered  in  various  ways.  Sometimes  it  is  changed  in- 
to a  lactescent  fluid,  holding  in  suspension  small,  albuminous 
flocculi;  at  others,  it  is  of  a  more  consistent  nature  and  of  a 
gelatinous  appearance,  and  is  deposited  on  the  free  surface 
of  the  membrane  in  the  form  of  small  particles,  which  are 
converted  into  layers  of  greater  or  less  extent.  These 
pseudo-membranous  productions  become  frequently  organ- 
ized, and  establish  permanent  adhesions  between  the  dif- 
ferent parts  of  the  organs  of  which  we  are  now  treating. 
In  cases  of  this  kind,  they  at  first  assume  the  firmness  of 
cellular  tissue,  and  finally  that  of  serous  membrane;  ves- 
sels may  also  be  observed  to  form  in  their  centre,  and  to 
inosculate,  by  their  ramifications,  with  those  of  the  surround- 
ing parts.  Their  mode  of  adhesion  to  the  original  mem- 
brane, as  well  as  their  disposition,  their  form  and  thick- 
ness, presents  a  great  number  of  varieties.  They  are  some- 
times found  under  the  form  of  bands,  filaments,  fringes, 
&c.  They  are  most  frequent  in  the  pleura,  and  the  peri- 
toneum; and  in  the  synovial  membranes  they  sometimes 
result  from  the  effects  of  rheumatism;  they  are  liable  to 
be  converted  into  cartilaginous  and  osseous  transforma- 
tions. It  should  also  be  observed,  that  inflammation  some- 
times terminates  in  the  secretion  of  purulent  matter,  which, 
according  as  it  is  more  or  less  thick,  and  more  or  less 
abundant,  remains  spread  on  the  free  surface,  or  forms  it- 
self into  a  collection  in  the  most  dependent  parts  of  the 
cavity.  The  chronic  phlegmasia,  sometimes,  convert 
portions  of  the  serous  tissue  into  the  fibrous,  cartilaginous 
and  the  osseous,  which  are  ordinarily  observed  under  the 


OF  THE  SEROUS  SYSTEM.  78 

form  of  layers,  either  on  the  adherent  surface  or  in  the 
thickness  of  the  membrane.  The  serous  surface  of  the 
pericardium  often  presents  examples  of  this  kind.  Concre- 
tions of  the  same  nature  as  the  preceding,  either  pedunculous 
or  entirely  unconnected,  are  sometimes  found  in  the  serous 
cavities,  and  especially  in  the  synovial.  Tubercles  also 
occur  sometimes  in  this  system. 

The  formation  of  the  accidental  serous  membranes, 
known  under  the  name  of  cysts,  is  generally  owing  to  a 
sub-inflammation,  or  at  least  to  a  constant  irritation  of  the 
cellular  tissue.  These  cysts,  which  have  been  demonstrat- 
ed by  Bichat  to  be  analagous  to  the  serous  membranes, 
mostly  result  from  the  condensation  of  the  cellular  tis- 
sue around  an  effusion  of  blood,  a  collection  of  matter, 
serum,  foreign  bodies,  &c.  &c.  Some  are  owing  to  the 
development  of  a  pre-existing  sac,  such  are  the  cysts 
which  result  from  the  dilatation  of  the  ovarian  vesicles, 
and  of  the  spermatic  cord,  produced  by  the  partial  disten- 
tion of  the  tunica  vaginalis  testis,  &c.  These  cysts  may 
present  all  the  grades  of  organization  of  the  serous  mem- 
branes, and  all  the  alterations  to  which  they  are  subject: 
they  exhale  and  absorb  the  same  fluids.  Hydatids  are  a 
kind  of  cysts  which  are  distinguished  from  the  others  in 
this,  that  they  do  not  adhere  to  the  neighbouring  parts. 
They  are  found  in  greater  or  less  numbers  in  some  organs, 
such  as  the  brain,  the  liver,  the  uterus,  &c.  In  the  serous 
membranes,  and  the  true  cysts,  they  are  filled  and  sur- 
rounded with  serum,  and  appear  to  result  from  the  organi- 
zation of  this  fluid: — the  consistency  of  their  parietes  re- 
sembles concrete  albumen.  These  productions  have  been 
placed  amongst  the  entozoaria,  by  M.  Laennec,  who  has 
described  them  under  the  name  of  acephalocystes,  while 
Cuvier,  Rudolphi  and  Meckel  have  denied  them  a  plaee 
in  their  zoological  table. 

The  accumulation  of  serum  in  the  cavities  of  the  serous 

membranes — a  kind  of  affection  which  constitutes  dropsy, 
11 


74  OP  THE  SERO-SPLANCHNIC  MEMBRANES. 

is  owing  to  a  want  of  equilibrium  between  the  exhalation 
and  absorption  of  this  fluid.  The  first  exceeds  its  ordina- 
ry tyPe>  and  constitutes  what  is  termed  active  dropsy;  it 
depends  most  frequently  on  inflammation,  which  may  be 
either  ephemeral  or  chronic:  when  the  exhalation  remains 
normal  and  the  absorption  is  languid,  it  is  called  passive 
dropsy,  and  often  results  from  a  disorder  of  the  circulation 
and  an  engorgement  of  the  venous  system, — a  frequent 
consequence  of  some  deep-seated  alteration  of  some  of  the 
viscera. 


section  2. 
Of  the  Sero-Splanchnic  Membranes. 

Definition. — The  sero-splanchnic  membranes  are  those 
which  line  the  visceral  cavities,  and  cover  more  or  less 
completely  the  organs  that  are  contained  within  them. 

Division. — The  sero-splanchnic  membranes  are  divided 
into  two  classes;  the  first  comprehends  the  tunica  arach- 
noides,  the  pericardium,  and  the  peritoneum;  the  second 
consists  of  the  two  pleura?,  and  the  two  tunicas  vaginales 
of  the  testes. 

General  conformation  and  arrangement. — These,  like 
the  other  serous  membranes,  form  shut  sacs;*  and  in  their 
general  arrangement  they  resemble  "those  night  caps  which 
are  folded  within  themselves/'  in  such  a  manner  as  to  form 
an  external  and  an  internal  lamina,  which  are  continuous 
where  they  are  reflected  the  one  upon  the  other,  and  con- 
tiguous by  one  of  their  surfaces.  The  external  or  parietal 
lamina  adheres  to  theparietes  of  the  splanchnic  cavity;  while 
the  internal  or  visceral  lamina  is  spread  upon  the  organs  con- 
tained within  it,  and  envelops  them  more  or  less  complete- 

*  It  must  not  be  forgotten  that  the  peritoneum  forms  an  exception  to 
this  general  character  of  the  serous  membranes,  by  the  fallopian  tubes 
penetrating  into  its  cayity. 


OF  THE  SER0-5PLAXCHNIC  MEMBRANES.  IO 

ly.  It  is  in  this  sense  that  we  distinguish  the  pleura  eos- 
talis  from  the  pleura  pulmonalis,  though  they  both  form 
really  but  one  serous  membrane  in  each  lateral  half  of  the 
chest  The  arrangement  of  the  external  la3~er  of  these 
membranes  presents  nothing  remarkable:  while  that  of  the 
internal  is  more  complicated,  especially  in  the  tunica  arach- 
noides,  and  the  peritoneum;  the  first  furnishing  a  sheath 
to  the  encephalic  blood-vessels  and  nerves,  and  the  second 
being  in  connexion  with  the  various  organs  of  the  abdomen 
and  pelvis.  The  parietal  layer  is  sometimes  suddenly  re- 
flected to  form  the  visceral,  and  to  cover  an  organ  that  it 
does  not  ordinarily  envelop  completely,  as  for  instance, 
in  the  ascending  and  descending  portions  of  the  colon. 
Sometimes,  also,  the  membrane  leaves  the  wall  of  the  ca- 
vity, runs  a  short  distance  before  it  covers  the  organ  to 
which  it  is  sent,  then  envelops  it  completely,  except  where 
its  blood-vessels  and  nerves  enter,  lines  these,  and  regains 
the  point  where  it  was  given  off.  From  this  arrangement 
result  a  number  of  folds,  which  derive  their  names  from 
the  organs  with  which  they  are  in  contact,  &c.  The  vis- 
ceral layer  differs  considerably  in  its  arrangement  from  the 
preceding;  after  having  covered  a  part  of  an  organ,  it  is 
extended  to  the  parietal  layer,  then  is  reflected  on  itself, 
and  envelops  the  other  portion.  The  folds  which  are 
formed  by  the  visceral  layer  are  either  loose  and  floating, 
as  the  omentum,  or  maintained  firmly  in  their  situation  by 
the  continuity  of  their  lateral  parts  with  the  parietal  layer, 
as  is  the  case  with  the  broad  ligaments  of  the  uterus.  In 
general,  the  layers  of  the  duplicatures  to  which  we  have 
just  alluded,  are  connected  by  loose  cellular  tissue  to  permit 
their  separation,  when  the  organ  to  which  they  corres- 
pond increases  in  volume. 

Surfaces. — The  external  surface  is  every  where  adhe- 
rent to  the  parietes  of  the  splanchnic  cavities,  to  the  different 
viscera,  to  their  blood-vessels  and  nerves,  and  to  itself  in  the 
folds  of  which  we  have  just  spoken:  the  tunica  arachnoides 


76  OP  THE  SERO-SPLANCIINIC  MEMBRANES. 

affords  the  only  example,  and  that  only  in  a  small  part  of 
its  extent,  where  the  external  surface  of  a  serous  membrane 
does  not  adhere.  We  have  already  pointed  the  manner, 
in  which  the  serous  membranes  are  connected  to  the  dif- 
ferent parts  which  they  cover,  and  we  have  only  to  add, 
that  their  union  is  less  firm  and  intimate  where  the  parietal 
layer  is  reflected  upon  the  organs.  With  regard  to  their 
free  surface,  we  have  nothing  to  add  to  what  was  said  in 
the  preceding  section. 

Texture. — The  sero-splanchnic  membranes  are  really 
nothing  but  large  meshes  of  cellular  tissue,  modified  with 
regard  to  its  density.  Their  fibrous  appearance  is  not  so 
well  marked,  nor  are  they  so  abundantly  supplied  with 
pellucid  vessels,  as  the  synovial  membranes.  No  nerves 
can  be  traced  into  them,  and  the  red  vessels  which  appear  to 
penetrate  them,  belong  to  the  subjacent  parts,  and  are  par- 
ticularly numerous  between  their  duplicatures,  where  there 
is  also  more  or  less  adipose  tissue. 

Physical  and  vital  properties. — The  extensibility  of 
the  sero-splanchnic  membranes  is  greater  than  that  of  the 
synovial,  but  their  other  physical  properties  and  their  vi- 
tality present  nothing  peculiar. 

Functions. — In  the  healthy  state,  the  quantity  of  fluid 
which  is  exhaled  on  the  free  surface  of  the  sero-splanchnic 
membranes,  is  so  small  that  it  merely  moistens  them.  It 
is  composed  principally  of  albumen,  and  when  exposed  to 
a  slightly  elevated  temperature,  most  of  it  coagulates;  ac- 
cording to  the  experiments  of  Beclard  the  incoagulable 
part  consists  of  gelatinous  mucus.  The  sero-splanchnic 
membranes  serve  to  insulate  the  viscera  from  each  other 
and  the  splanchnic  parietes,  at  the  same  time  that  they  fa- 
cilitate their  reciprocal  motions  by  the  polish  and  smooth- 
ness of  their  free  surface.  They  also  strengthen  and  pro- 
tect a  great  number  of  blood-vessels  in  the  visceral  cavities 
by  giving  them  an  additional  sheath,  and  line  most  of  the 
membraniform  organs. 


OF  THE  SYNOVIAL  MEMBRANES.  77 

Pathological  Anatomy. 

The  form  of  these  membranes,  as  well  as  their  relations 
with  the  neighbouring  organs,  are  frequently  altered  by- 
collections  of  serum.  These  alterations  are  also  sometimes 
owing  to  displacements  of  the  viscera,  particularly  to  those 
which  result  from  hernias— a  kind  of  affection  to  which  all 
the  organs  of  the  abdomen,  and  especially  the  intestinal 
canal,  are  subject.  The  organ  that  passes  out  of  the 
splanchnic  cavity,  being  generally  covered  by  a  layer  of 
serous  membrane,  pushes  with  it  a  portion  of  the  parietal 
sac  which  is  placed  before  the  opening  through  which  it 
escapes,  and  which  furnishes  thus  a  second  envelope  that 
is  contiguous  to  the  first,  and  constitutes  the  herniary  sac. 
This  sac  is  often  formed  by  the  distention  of  the  parietal 
layer — as  in  cases  of  umbilical  hernias. — The  alterations 
of  texture  of  the  sero-splanchnic  membranes  having  already 
been  pointed  out  in  the  preceding  section,  it  is  only  neces- 
sary to  add,  that  they  are  more  frequent  in  these  than  in 
the  synovial  membranes. 


section  3. 
Of  the  Synovial  Membranes. 

Definition. — The  synovial  membranes  are  those  which 
line  the  surfaces  of  the  articular  cartilages,  and  are  inter- 
posed between  the  surfaces  that  move  upon  each  other  in 
the  different  parts  of  the  body. 

Division. — These  membranes  are  divided  into  the  sub- 
cutaneous bursae  mucosas,  the  synovial  membranes  of  the 
tendons,  and  those  of  the  articulations. 

Form  anal  arrangement  of  the  subcut.  bursae  mucosse. 
— The  subcutaneous  bursse  mucosse  are  small  spherical 
bags,  which  are  interposed  between  the  skin  and  certain 
osseous  parts  or  cartilaginous  projections.  They  are  of 
different  sizes  and  firmness,  and  are  connected  to  the  sur- 


78  OF  THE  SYNOVIAL  MEMBRANES. 

rounding  parts  by  cellular  substance;  they  often  commu- 
nicate with  the  tendinous  capsules;  are  contiguous  to  them- 
selves by  their  internal  surface;  and  some  of  them  are  di- 
vided into  several  cavities  by  septa,  which  are  more  or  less 
complete.* 

Form  and  arrangement  of  the  synovial  membranes 
of  the  tendons. — The  synovial  membranes  of  the  tendons 
may  be  arranged  under  two  classes,  the  spherical  and  the 
vaginal.  The  spherical  are  placed  most  frequently  be- 
tween the  tendons  of  muscles,  and  between  the  tendons 
and  some  of  the  bones,  &c.  They  embrace  these  organs 
more  or  less  completely,  and  are  veiy  intimately  connected 
to  them  by  their  external  surface,  which  often  communi- 
cates with  the  subcutaneous  bursas,  or  the  synovial  mem- 
branes of  the  joints.  Within  some  of  these  bursas  are 
small  folds  with  fimbriae  appended  to  them,  and  covered  by 
a  continuation  of  the  internal  membrane  of  the  bursas. 
The  vaginal  bursas,  so  called  from  their  forming  complete 
sheaths  around  the  tendons,  consist  of  two  cylindrical  mem- 
branes, which  are  continuous  at  their  two  extremities,  and 
are  connected  to  the  surrounding  parts  by  cellular  sub- 
stance. In  some  regions,  one  of  the  extremities  of  these 
tendinous  sheaths  is  divided  into  several  portions  in  the 
form  of  small  bands,  which  are  continued  upon  different 
tendons. 

Form  and  arrangement  of  the  synovial  membranes  of 
the  articulations. — These  membranes  form  shut  sacs  of 
the  finest  texture,  are  of  a  spherical  form,  and  line  the  sur- 
faces of  the  diarthrodial  joints,  their  ligaments,  and  the 
parts  which  immediately  surround  them.  Their  number, 
form  and  arrangement,  differ  in  the  different  joints;  thus  in 
some  of  the  articulations,  such  as  the  ileo-femoral,  the 
synovial  capsule  is  reflected  upon  the  inter-articular  liga- 

*  To  Beclard  is  due  the  honour  of  having  given  the  first  good  descrip- 
tion of  these  small  organs. 


OF  THE  SYNOVIAL  MEMBRANES.  79 

ment,  which  gives  it  a  kind  of  vaginal  appearance.  In  the 
knee-joint,  its  reflections  are  still  more  complicated  on  ac- 
count of  the  great  number  of  ligaments,  and  the  tendons  to 
which  it  furnishes  more  or  less  complete  sheaths.  The 
synovial  membranes  adhere  to  the  ligaments  and  perios- 
teum, which  they  cover  in  such  a  manner  that  they  can  not 
be  separated  without  difficulty:  and  their  connexion  with 
the  articular  cartilages  is  so  intimate  that  they  scarcely  ad- 
mit of  being  detached;  so  that  several  anatomists,  and 
amongst  others,  M.  Magendie,  have  denied  its  existence  in 
the  central  portions  of  the  cartilages;  but  a  careful  ex- 
amination, as  well  as  facts  derived  from  pathological  anato- 
my, such  particularly  as  pseudo-membranous  adhesions  on 
the  centre  of  the  articular  surfaces,  will  at  once  convince 
us  of  the  incorrectness  of  the  opinions  of  those  who  would 
deny  its  existence.  The  synovial  membranes  of  the  joints 
have  loose  folds  which  are  analagous  to  those  of  the  sero- 
splanchnic  membranes,  and  are  called  fimbriated  pro- 
longations. These  duplicatures  contain  cellular  tissue  and 
blood-vessels,  as  well  as  small  masses  of  fat,  which  Havers 
improperly  described  as  glands,  and  which  have  been 
named  by  his  successors  in  honour  of  him,  glandulse 
Haveri. 

Texture. — The  tissue  of  the  synovial  membranes,  es- 
pecially that  of  the  first  two  varieties,  can  be  distinguished 
from  the  cellular  tissue  only  by  its  greater  density.  Some 
of  the  synovial  membranes  of  the  joints  appear  to  have  lym- 
phatic vessels;  but  no  nerves  can  be  traced  into  any  of  them, 
and  their  vessels,  which  do  not  carry  red  blood  in  the 
healthy  state,  can  be  seen  only  when  they  are  inflamed. 

Characters  and  physical  properties. — All  the  synovial 
membranes  are  whitish,  semi-transparent,  soft  and  thin; 
and  their  sensibility  appears  to  be  less  than  that  of  the 
sero-splanchnic  membranes. 

Vital  properties. — The  vitality  of  the  synovial  mem- 


80  OF   THE  SYNOVIAL  MEMBRANES. 

branes,  like  that  of  the  other  serous  membranes,  is  ren- 
dered evident  only  by  inflammation. 

Differences  according  to  age. — The  subcutaneous  bursas 
can  easily  be  distinguished  at  the  period  of  birth;  their 
synovia  being  then  more  abundant  than  at  any  other  period 
of  life.  Their  extent  and  density  augment,  in  proportion 
as  the  parts  where  they  are  found  are  exercised.  Accord- 
ing to  the  observations  of  Beclard,  Bogros,  Breschet,  and 
Villerme,  the  synovial  membranes  of  the  tendons  are  de- 
veloped subsequently  to  the  friction  of  the  tendons  of  the 
neighbouring  parts.  They  are  formed,  indeed,  in  every 
part  where  the  skin  becomes  the  seat  of  habitual  pressure, 
as  for  instance,  in  the  stumps  of  amputated  limbs.  Soem- 
mering observes,  that  the  bursas  diminish  in  number  as  we 
advance  in  life,  by  uniting  with  those  with  which  they  are 
contiguous.  Finally,  the  synovial  membranes,  very  fine 
and  delicate  in  the  foetus  and  infant,  become  more  dense 
and  compact  in  the  adult;  in  old  age,  they  acquire  a 
certain  degree  of  rigidity,  exhale  less  synovial  fluid,  are 
dry,  and  contribute  not  a  little  by  the  state  in  which  they 
are,  to  the  slowness  of  motion  which  marks  this  period  of 
life. 

Functions. — The  synovial  membranes  serve  to  facilitate 
the  reciprocal  motions  of  the  parts  between  which  they 
are  situated,  both  by  the  smoothness  of  their  surface,  and 
the  presence  of  the  synovial  fluid,  which  is  constantly  ex- 
haled and  absorbed.  This  fluid  is  more  abundant  on  the 
fimbriated  prolongations,  and  is  derived  from  the  numer- 
ous blood  vessels  which  are  distributed  between  the  reflec- 
tions of  these  membranes,  and  not,  as  was  said  by  Havers, 
from  the  elaboration  of  a  glandular  apparatus.  The  syno- 
vial fluid  exudes  from  every  part  of  the  free  surface  of  the 
synovial  membranes — a  fact,  which  in  itself  is  sufficient  to 
overthrow  the  hypothesis  of  Haver:,. — It  differs  both  in 
quantity  and  properties  in  the  different  kinds  of  synovial 
membranes.     In  the  bursas  mucosas  it  is  merelv  sufficient 


OF  THE  SYNOVIAL  MEMBRANES.  81 

to  lubricate  the  membrane,  and  to  render  it  unctuous  to 
the  touch;  in  the  tendinous  pouches,  it  is  more  abundant, 
of  a  thick  viscid  consistence,  and  of  a  yellowish  red  tint, 
composed  of  albumen  and  mucus.  In  the  articular  mem- 
branes it  is  equally  viscid  and  ropy,  of  a  saline  taste,  com- 
posed of  water,  albumen,  fibrin,  mucus,  of  some  of  the 
salts  of  soda  and  lime,  and,  according  to  the  analysis  of 
Fourcroy,  of  a  small  quantity  of  uric  acid. 

Pathological  Anatomy. 

Dropsy  of  the  subcutaneous  bursas,  {hygroma),  and  of 
the  synovial  sheaths  of  the  tendons  (ganglion)  is  by  no 
means  a  rare  disease;  while  that  of  the  articular  synovial 
membranes  (hydrarthrosis)  is  seldom  found  to  occur. 
The  synovial  fluid  sometimes  accumulates  in  considerable 
quantities,  and  preserves  its  normal  character;  at  others,  it 
is  altered  in  various  ways.  In  the  first  two  varieties,  it  fre- 
quently resembles  currant-jelly,  both  in  colour  and  consist- 
ence. Inflammation  of  the  synovial  membranes  often  ter- 
minates by  the  secretion  of  puriform,  or  purulent  matter, 
produces  ulceration,  or  fungous  growths,  and  converts  the 
articular  capsules  into  a  gray  striated,  pultaceous  substance,, 
which  gradually  invades  the  whole  joint.  It  also  some- 
times terminates  in  a  thickening  of  the  membranes,  and  in 
the  formation  of  pseudo-membranous  adhesions,  which  vary 
in  form  like  those  of  the  other  serous  membranes.  Some- 
times there  are  small  bands,  or  cords,  which,  by  their  num- 
ber and  direction,  represent  a  kind  of  cellular  appearance; 
at  others,  there  are  membraniform  layers  which  unite  the 
free  and  contiguous  surfaces,  and  produce  permanent  ad- 
hesions. All  these  affections  impede  the  motions  of  the 
parts  between  which  the  membrane  is  interposed,  and  con- 
stitute a  variety  of  false  anchylosis — a  disease  which  also 
frequently  results  from  a  thickening  and  induration  of  the 
articular   synovial   membrane    and   the   adjacent  tissues. 

When  the  contiguous  parts  of  a  joint  adhere,  the  synovial 
12 


82  BIBLIOGRAPHY  OF  THE  SEROUS  SYSTEM. 

capsule  and  the  articular  cartilages  are  gradually  absorbed; 
the  extremity  of  the  bones  unite,  and  constitute  what  is 
termed  true  anchylosis.  Foreign  bodies,  such  as  cartila- 
ginous concretions,  &c,  are  not  unfrequent  in  the  synovial 
membranes,  especially  in  those  of  the  tendons,  which  also, 
now  and  then,  contain  small  bodies  of  the  size  and  shape 
of  a  pear-seed,  which  have  been  falsely  supposed  to  be  en- 
dowed with  life. — The  synovial  membranes  of  the  joints 
are  sometimes  subject  to  fibrous,  cartilaginous,  and  osseous 
concretions,  which  are  either  loose,  or  adherent,  or  lodged 
in  the  thickness  of  the  articular  cartilage; — saline  concre- 
tions, composed  principally  of  the  urate  of  soda,  are  some- 
times found  in  the  articulations;  and  under  certain  circum- 
stances new  synovial  membranes  are  formed,  especially 
between  the  fragments  of  a  broken  and  disunited  bone. 

Bibliography  of  the  Serous  System. 

1.  Sero-splanchnic  system. 

Bichat.  Traite  des  Membranes.     Paris,  an  VIII;  pag.  73; 

III,  202—292. 
Anatomie  generale,  torn.  IV,  pag.  108  et  suiv.  edit. 

citee. 
J.  F.  Meckel.  Ouv.  cit. 
P.  Ji.  Bkclard.   Ouv.  cit. 
Bonn.  De  continuationibus  membranorum.  Amst.  Batav., 

1763. 
Langenbeck.  Commentarium  de  structura  peritonii,  etc. 

cum  tabulis.  Gottingen,  1817. 

2.  Synovial  System. 

Fourcroy.  Six  Memoires  pour  servir&l'Hist.  anatom.  des 
Tendons,  dans  lesquels  on  s'occupe  specialement  de  leur 
caps,  muq,;  dans  les  Memoires  de  l'Acad.  royale  des 
Sciences.  Paris,  17S5 — SS. 

Koch  et  Eysold.  De  bursis  tendinum  mucosis.  Witten- 
burg.  1789. 


BIBLIOGRAPHY  OF  THE  SEROUS  SYSTEM.  83 

Ch.  M.  Rosenmuller.    Icones  et  descript.  bursar,  mucos. 

corp.  hum.  Leipsig,  1799. 
Jl.  Hdvers.  Osteologia  nova.  Londres,  1691. 
Brodie.    Traite   des   maladies   des  Articulations.    Paris, 

1819. 
Margueron.  Annales  de  Chimie,  torn.  IV. 
J.  Cloquet.   Notes  sur  les  Ganglions.  (Arch,  gener.  de 

med.,  torn.  IV,  pag.  23.2.) 


S4  OF  THE    FIBROUS  SYSTEM. 


CHAPTER  IV. 

OF  THE  FIBROUS  SYSTEM. 

FIRST  DIVISION. 
OF  THE  FIBROUS  SYSTEM,  PROFERLY  SO  CALLED. 

SECTION  1. 

General  Observatio?is. 

Synonymu:  Albugineous  tissue,  tendinous  tissue,   aponeurotic  tissue, 
ligamentous  tissue. 

Definition. — The  fibrous  system  consists  of  an  assem- 
blage of  organs,  which  present  various  forms,  serve  differ- 
ent purposes,  but  are  all  composed  of  a  white  shining  tis- 
sue, which  is  firm  and  strong,  and  consists  of  more  or  less 
distinct  fibres. 

Division. — The  fibrous  tissue,  may  be  distinguished  in- 
to several  classes:  1st,  into  the  fibrous  ligamentous  or- 
gans, which  comprehend  the  tendons  and  the  ligaments 
properly  so  called;  2d,  into  the  fibrous  envelopes,  which 
consists  of  the  aponeuroses  of  the  muscles,  the  periosteum 
of  the  bones,  the  perichondrium  of  the  cartilages,  the  dura 
mater  of  the  brain,  the  sclerotica  of  the  eye,  the  tunica  albu- 
ginea  of  the  testis,  the  glandular  coverings,  &:c.  &c. 

General  conformation. — There  are  two  principal  forms 
in  the  fibrous  system,  the  fascicular  and  the  membranous; 
the  first  belongs  exclusively  to  the  tendons  and  the  liga- 
ments; the  second  to  the  fibrous  envelopes,  and  in  part,  also 


OP  THE    FIBROUS  SYSTEM.  S5 

to  the  ligaments  and  tendons.  From  the  fact,  that  the  ten- 
dons, the  ligaments  and  aponeuroses,  as  well  as  the  dura  ma- 
ter, and  the  fibrous  envelope  of  the  corpora  cavernosa,  are 
connected  with  the  periosteum,  Bichat  has  represented  this 
membrane  as  the  basis  of  the  fibrous  organs;  but  as  some  of 
the  glandular  envelopes,  which  belong,  like  the  preceding 
organs,  to  the  fibrous  system,  have  no  relation  of  continuity 
with  it,  we  are  not  warranted  in  admitting  this  distinction. 

Texture. — All  the  fibrous  organs  are  composed  of  an 
assemblage  of  fibres,  which  are  more  distinct  in  some  parts 
than  in  others;  they  are  either  disposed  in  fasciculi  which 
are  almost  parallel  with  each  other,  or  they  are  inter- 
woven in  different  ways,  and  form  thin  and  cross  layers, 
as  in  the  aponeuroses.  These  fibres  consist  of  white  fila- 
ments which  are  more  fine  and  delicate  than  hairs,  and 
enjoy  all  the  physical  properties  which  belong  to  the  tissue 
which  they  compose.  In  his  classification  of  the  elementary 
tissues,  M.  Chaussier  has  applied  the  name  of  albugineous 
fibre  to  the  tissue  of  which  we  are  treating;  but  most  phy- 
siologists of  the  present  day,  consider  it  as  merely  a 
very  condensed  variety  of  the  cellular  tissue.  This 
tissue  surrounds  and  connects  every  fasciculus,  every 
fibre,  and  furnishes  a  sheath,  or  covering  to  the  organs 
which  they  form.  No  nerves  have  as  yet  been  traced  into 
the  fibrous  tissue;  it  contains  but  little  adipose  substance, 
and  its  degree  of  vascularity  differs  in  the  different  classes 
of  fibrous  organs;  thus  the  periosteum  and  the  dura  mater 
are  abundantly  supplied  with  blood-vessels,  while  some 
of  the  tendons,  especially  the  large  ones,  appear  to  be 
destitute  of  them.  There  are  some,  which  receive  lym- 
phatics. 

Characters,  physical  and  chemical  properties.  — The 
fibrous  tissue  is  of  a  brilliant  white,  argentine  colour,  firm 
and  resisting,  and  stretched  with  difficulty.  When  this, 
however,  takes  place  suddenly,  the  cause  of  resistance  is 
sometimes  overcome,  and  the  organ  is  torn;  often,  howev- 


S6  OP  THE  FIBROUS  SYSTEM. 

er,  this  resistance  is  greater  than  that  of  the  bones  &c,  to 
which  it  is  attached.  The  fibrous  tissue,  having  but  little  ex- 
tensibility, is  sometimes  subject  to  accidents,  known  under 
the  name  of  strangulations,  which  consist  in  the  insupe- 
rable obstacle  which  the  fibrous  organs  present  to  the  de- 
velopment of  the  parts  which  are  ordinarily  surrounded 
by  them,  and  whose  volume  is  suddenly  augmented  by 
violent  inflammation  or  other  causes.  It  possesses  but  lit- 
tle elasticity,  at  least  in  its  fresh  state;  it  retracts  with  a 
degree  of  slowness  proportionate  to  that  of  its  distention. 
By  desication,  it  becomes  somewhat  elastic,  transparent, 
of  a  yellowish  red  colour,  and  almost  homogeneous;  but  by 
submitting  it  to  the  action  of  water,  for  a  short  time,  it  re- 
covers all  its  original  characters.  After  long  maceration, 
its  fibres  separate,  and  are  changed  into  a  soft,  whitish 
pulp,  which,  by  the  action  of  ebullition,  is  resolved  into 
gelatine.  It  is  very  difficult  of  digestion,  and  when  expos- 
ed to  putrefaction,  it  resists  its  action  for  a  considerable 
time. 

Vital  properties. — In  the  healthy  state,  the  sensibility 
of  the  fibrous  tissue,  as  we  have  already  seen,  is  rendered 
evident  by  violent  distentions,  such  as  sprains,  which  pro- 
duce excessive  pain,  and  often  give  rise  to  the  most  in- 
tense inflammation.*  Nevertheless,  if  a  fibrous  organ  be 
punctured,  divided,  or  submitted  to  the  action  of  chemical 
irritants,  the  animal  will  not  evince  the  least  symptom  of 
pain:  though  sometimes,  these  causes  may  be  capable  of 
acting  upon  this  tissue  in  such  a  manner  as  to  excite  in- 
flammation. The  fibrous  tissue  is  destitute  of  contractility 
of  texture;  and  when  injured,  it  is  often  readily  repaired. 

Mode  of  development,  and  differences  according  to 
age. — The  fibrous  tissue  can  be  distinguished  about  three 
months  after  impregnation:  in  the  infant,  it  is  of  a  pearly, 

*  Many  persons,  and  we  amongst  the  rest,  believe,  contrary  to  the 
generally  received  opinion,  that  this  pain  ought  to  be  attributed  rather 
to  the  nerves  of  the  injured  part,  than  to  the  ligaments  themselves. 


OP  THE  FIBROUS  SYSTEM.  87 

white  appearance,  and  yields  readily  to  the  extensive  mo- 
tions which  are  performed  at  this  period,  and  being  more 
extensible,  it  breaks  less  easily.  At  this  period,  the  peri- 
osteum, the  dura  mater,  and  the  sclerotica,  are  .compara- 
tively more  developed  than  in  the  subsequent  periods  of 
life.  In  old  age,  the  fibrous  tissue  becomes  more  compact 
and  inflexible,  more  yellow  and  less  shining  than  in  the 
adult.  Notwithstanding  its  hardness,  it  seldom  ossifies, 
except  in  those  regions  where  it  is  exposed  to  the  friction 
of  the  bones,  or  in  the  neighbourhood  of  the  cartilages. 

Functions. — The  functions  of  the  fibrous  system  vary 
in  the  different  fibrous  organs,  and  are  all  purely  me- 
chanical. 

pathological  Jlnatomy. 

When  a  fibrous  organ  has  been  extended,  it  becomes 
elongated  and  thickened,  and  with  difficulty  recovers  its 
former  state.  Wounds  of  these  organs  heal  by  the  effusion 
of  adhesive  matter  which  closes  up  their  lips,  and  acquires 
the  density  of  fibrous  tissue.  Inflammation  seldom  termi- 
nates in  gangrene  or  suppuration,  but  most  frequently  by 
resolution  or  a  thickening  of  the  organ.  The  chronic 
phlegmasia?  of  the  fibrous  organs  often  produce  cartilaginous 
and  osseous  growths,  the  development  of  fungous  polypi, 
and  carcinomatous  tumours.  The  fibrous  tissue  is  some- 
times accidentally  developed  around  cysts,  tumours,  false 
anchyloses,  and  in  the  pseudo-membranous  adhesions  of 
the  serous  membranes.  The  cicatrices  of  the  liver  and 
the  skin  consist  of  a  tissue  analagous  to  the  fibrous,  and  the 
development  of  some  polypi  and  subcutaneous  tumours, 
especially  those  that  occur  between  the  rectum  and  the 
vagina,  and  between  it  and  the  bladder,  may  also  be  refer- 
red to  it.  Fibrous  bodies  are  also  sometimes  found  in  cer- 
tain parts  of  the  body,  especially  in  the  uterus  and  the 
ovaries,  which  are  often  confounded  with  schirrus,  though 
they  are  entirely  different.  They  are  more  or  less  numer- 
ous, are  round  and  lobulated,  small  and  soft,  and  gradually 


88  OF  THE  FIBItOUS  SYSTEM. 

increase  in  volume  and  density.  They  arc  formed  of  two 
layers;  one  of  which  is  fibrous,  the  other  of  a  homogeneous 
texture,  and  consists,  according  to  the  researches  of  J.  F. 
Meckel,  of  fibro-cartilage.  They  are  frequently  organized, 
and  are  sometimes  converted  into  cartilaginous  and  osseous 
substances:  the  calculi  which  occur  in  the  uterus  are  often 
nothing  but  lobes  of  these  bodies'. 


SECTION  2. 

Of  the  Organs  Co7?iposing  the  Fibrous   System,  Pro- 
perly so  Called. 

ARTICLE    1. 

Of  the  Fibrous  Ligamentous  Organs. 

The  fibrous  ligamentous  organs  comprehend  the  liga- 
ments of  the  bones  and  cartilages,  and  the  tendons  which 
unite  the  muscles  to  the  hard  parts. 

§  1.      Of  the  Ligaments. 

Definition. — Ligaments  are  strong  fibrous  organs,  \2.vy- 
ing  in  form,  and  adhering  to  the  bones  or  cartilages. 

Division. — The  ligaments  are  divided  according  to  their 
situation:  1st,  into  articular,  or  those  which  are  attached 
to  the  ends  of  the  articulating  bones;  2d,  into  non-articu- 
lar, or  those  which  pass  from  one  part  of  a  bone  to  ano- 
ther, either  to  convert  a  fissure  into  a  foramen,  as  the 
coraco-acromion  ligament  of  the  scapula,  or  to  obliterate  an 
osseous  aperture,  as  the  sub-pubic  ligament,  for  the  pur- 
pose of  giving  origin  to  muscles;  3d,  into  mixed,  or  those 
which  supply  the  place  of  bones,  and  increase  the  extent 
of  surface  for  the  attachment  of  muscles;  as  the  inter-os- 
seous peroneo-tibial,  the  radio-cubital,  and  the  saero-sciatic 
ligaments. 


OF  THE  FIBROUS  SYSTEM.  89 

Conformation  and  arrangement. — All  the  different 
classes  of  ligaments  have  the  two  general  forms  of  the  fi- 
brous organs,  the  fascicular  and  the  membranous.  The  fasci- 
cular ligaments  are  generally  of  an  irregular  quadrilateral 
form,  seldom  triangular,  composed  of  white  fasciculi,  ar- 
ranged in  parallel  lines,  and  connected  by  cross  fibres.  The 
articular  ligaments  are  termed  external  or  internal,  accord- 
ingly as  they  are  situated  in  relation  to  the  joint.  Most  of 
the  external  ligaments  are  situated  laterally,  and  in  such  a 
manner  as  to  confine  or  prevent  lateral  motion;  internally 
they  adhere  to  the  synovial  membrane,  externally  to  the 
tendons,  &c.  which  surround  the  joint.  The  internal  liga- 
ments are  white  fibrous  cords,  which  are  situated  within 
the  knee  and  the  ilio-femoral  articulation,  and  are  attached 
by  their  extremities  to  the  centre  of  the  articular  surface, 
and  adhering  in  the  rest  of  their  extent  to  the  synovial 
membrane,  which  is  reflected  upon  them  so  as  to  form  a 
sheath.  The  membranous  ligaments  vary  in  form,  and  are 
composed  of  distinct  fasciculi,  which  are  more  or  less  inti- 
mately connected  with  the  periosteum.  The  capsular  liga- 
ments form  large  fibrous  sacs,  which  surround  some  of  the 
moveable  joints,  and  are  attached  by  each  of  their  extre- 
mities to  the  circumference  of  the  osseous  parts,  which 
enter  into  the  composition  of  the  joints.  They  adhere 
firmly  by  their  internal  surface  to  the  external  surface  of  the 
synovial  membrane,  and  by  the  other,  to  the  peri-articular 
tissues. 

In  infancy,  the  ligaments  are  almost  exclusively  inserted 
into  the  periosteum,  and  their  connexion  with  the  bones 
and  cartilages  is  loose  and  feeble,  while  it  becomes  more 
firm  as  we  advance  in  years,  and  extremely  intimate  in 
old  age. 

Texture. — The  ligaments  are  of  a  firm  compact  texture, 
of  a  yellowish  colour,  and  composed  of  fibres  which  are 
more  distinct  in  some  than  in  others.  They  receive  blood- 
vessels and  lymphatics,  and  have  a  small  quantity  of  fat, 
13 


90  OF  THE  FIBROUS  SYSTEM. 

which  it  is  difficult  to  distinguish  at  first  sight.  They  pos- 
sess but  a  small  share  of  elasticity  and  sensibility,  though 
according  to  some  anatomists,  nerves  may  be  traced  into 
their  substance. 

Functions. — The  functions  of  the  ligaments  differ  in 
the  different  classes  of  ligaments;  thus  the  articular  liga- 
ments connect  the  extremities  of  the  moveable  bones, 
while  the  non-articular  and  mixed  serve  to  convert  certain 
bony  fissures  into  foraminse,  and  to  increase  the  extent  of 
surface  for  the  attachment  of  muscles,  &c. 

Alterations. — The  ligaments,  especially  the  capsular, 
are  often  ruptured, — inflamed, — relaxed, — thickened, — 
reduced  to  a  lardaceous  spongy  substance,  and  ossified. 

§  2.     Of  the  Tendons.  • 

Definition. — The  tendons  are  the  fibrous,  ligamentous 
organs,  which  unite  the  muscles  to  the  bones  or  cartilages, 
or  even  two  portions  of  the  same  muscle. 

Division. — They  are  divided  according  to  their  form, 
into  funicular  and  aponeurotic  tendons. 

Situation  and  relations. — The  tendons  are  most  com- 
monly situated  at  the  extremities  of  the  muscles,  and  are 
connected  to  them  by  one  extremity,  and  by  the  other  to 
the  bones,  or  the  aponeurotic  envelopes.  The  tendons 
sometimes  interrupt  the  continuity  of  the  fleshy  fibres,  and 
give  the  muscle  a  digastric  appearance,  &c.  In  some  in- 
stances, the  funicular  and  aponeurotic  tendons  occur  on  the 
same  muscles,  and  when  this  is  the  case,  the  first  is  attach- 
ed to  the  more  moveable  part,  and  the  second  to  that  which 
serves  as  the  fixed  point.  The  union  of  the  tendons  with 
the  fleshy  fibres  is  every  where  firm  and  intimate.  In  some 
places  the  muscular  fibres  run  from  both  sides  obliquely 
downwards  or  upwards,  to  a  tendon  in  the  middle  of  a 
muscle  and  form  an  arrangement  analogous  to  the  plumage 
of  a  feather;  or  the  tendinous  fibres  follow  the  direction  of 


OF  THE  FIBROUS  SYSTEM.  91 

the  muscular,  with  which  they  appear  to  be  continuous. 
In  some  instances  the  tendons  are  more  or  less  completely 
surrounded  by  synovial  bursas;  are  contained  in  fibrous 
sheaths,  and  are  in  relation  with  loose  cellular  tissue. 

Conformation. — The  funicular  tendons  are  elongated, 
rounded  or  flattened  cords,  some  being  single  in  their 
whole  extent,  others  divided  at  one  of  their  extremities 
into  several  distinct  portions.  The  aponeurotic  tendons, 
like  the  funicular,  are  either  single  or  divided;  in  some  in- 
stances they  form  arches  for  the  passage  of  blood-vessels 
and  nerves,  and  are  inserted  by  their  extremities  into  the 
bones;  others  are  partly  funicular,  and  partly  membrani- 
form.  In  some  instances  the  muscles  terminate  in  very 
short,  separate  fasciculi,  which  are  connected  to  one  or  the 
other  kind  of  tendons  to  which  we  have  just  alluded. 

Texture. — The  tendons  are  of  a  firm  compact  texture, 
are  composed  of  condensed  cellular  tissue,  and  their  fibres, 
which  are  white  and  small,  are  intimately  united  to  each 
other  by  cellular  tissue.  They  have  but  few  blood-vessels, 
and  neither  nerves  nor  lymphatic  vessels  have  been  traced 
into  their  substance. 

Characters,  physical  and  vital  properties. — The  ten- 
dons are  of  a  pearly  white  appearance,  dry,  tough,  and 
inextensible;  their  vitality,  especially  that  of  the  funicular, 
appears  to  be  less  than  that  of  the  other  fibrous  organs. 

Functions. — The  tendons  serve  to  unite  the  muscles  to 
the  bones  and  cartilages,  and,  by  atfording  a  more  exten- 
sive surface  of  insertion  to  the  muscular  fibres,  to  facilitate 
their  action. 

Alterations.— The  tendons  are  seldom  inflamed;  but 
when  they  are  bruised  or  otherwise  injured,  they  become 
affected  with  indolent  swellings,  which  continue  for  a  long 
time.  They  participate  in  the  softing  of  the  ligaments  in 
cases  of  white  swelling,  and  when  exposed  to  the  air  and 
deprived  of  their  cellular  tissue,  they  mortify  and  exfoliate. 


92  OF  THE  FIBKOUS  SYSTEM. 

ARTICLE    2. 

Of  the  Fibrous  Envelopes. 

The  fibrous  envelopes  comprehend:  1st,  the  aponeuroses, 
or  fibrous  envelopes  of  the  muscles;  2d,  the  sheaths  of  the 
tendons;  3d,  the  periosteum;  4th,  the  perichondrium;  5th, 
the  dura  mater,  the  sclerotica,  albuginea,  &c.  &c. 

§  1.     Aponeurotic  Envelopes. 

Definition. — The  aponeuroses  are  fibrous  membranes 
which  cover  more  or  less  completely  one  or  more  muscles. 

Division. — They  are  divided  into  general  and  partial; 
the  first  belong  to  the  extremities,  the  second  to  the  trunk. 

Conformation  and  arrangement. — The  general  enve- 
lopes represent  the  form  of  the  extremities  whose  muscles 
they  surround.  By  their  internal  surface  they  are  in  con- 
tact with  the  muscles,  and  send  membranous  elongations 
between  them,  which,  in  separating  them  from  each  other, 
furnish  points  of  attachment  to  some  of  their  fibres,  and 
go  to  be  inserted  into  osseous  eminences.  The  external 
surface  is  united  by  loose  cellular  substance  to  the  tegu- 
ments, the  adipose  tissue,  and  the  subcutaneous  vessels. 
At  their  extremities,  the  general  aponeuroses  are  confound- 
ed with  the  periosteum  or  cellular  tissue,  and  form  fibrous 
rings  for  the  passage  of  tendons.  The  partial  aponeu- 
roses vary  in  form,  and  serve  to  envelop  but  incompletely 
the  muscles  of  the  parietes  of  the  splanchnic  cavities. 
There  are  some  which  cover  but  one  muscle,  as  the  tem- 
poral, while  others  envelop  several;  some  correspond  by 
their  internal  surface  to  the  muscles  which  they  cover, 
and  by  the  external  to  the  subcutaneous  cellular  tissue: 
others  are  in  contact  with  the  muscles  on  both  surfaces, 
and  consist  of  several  layers  which  contain  these  muscles 


OF  THE  FIBROUS  SYSTEM.  93 

between  them,  as  in  a  kind  of  pouch;  an  example  of  which 
is  seen  in  the  aponeuroses  of  the  recti  muscles  of  the  ab- 
domen. 

The  aponeuroses  have  generally  one  or  more  tensor 
muscles  that  are  inserted  into  them,  either  in  whole  or  in 
part,  which  are  destined  to  give  them  a  degree  of  tension 
or  relaxation  proportioned  to  the  state  of  the  surrounding 
muscles.  This  arrangement  is  remarkable  in  the  insertion 
of  the  tensor  vaginas  femoris  into  the  fascia  lata  of  the 
thigh;  of  the  biceps  brachialis  into  the  anti-brachial  apo- 
neurosis, &c. 

Texture. — The  aponeurotic  envelopes-  are  composed  of 
one  or  more  layers  of  fibres,  which  pass  in  various  direc- 
tions. 

Physical  characters. — The  aponeurotic  envelopes  are  of 
a  pearly  white  appearance;  their  thickness  is  in  direct 
ratio  with  the  number,  force  and  activity  of  the  muscles 
which  they  envelop.  Their  fibres  are  more  inflexible  and 
resisting  than  those  of  the  tendons,  and  yield  less  readily 
to  maceration  and  the  action  of  ebullition. 

Functions. — The  aponeuroses  serve  to  maintain  the 
subjacent  parts  in  their  natural  situation;  to  cover  and  in- 
sulate the  muscles;  to  facititate  the  circulation  of  the  ven- 
ous and  lymphatic  fluids,  and,  by  their  want  of  extensibi- 
lity, to  prevent  their  accumulation. 

§  2.     Of  the  Tendinous  Sheaths. 

Definition. — The  tendinous  sheaths  are  the  expansions 
of  the  fibrous  tissue,  which  form,  either  alone,  or  in  con- 
junction with  the  neighbouring  parts,  a  kind  of  canal  for 
the  passage  of  one  or  more  tendons. 

Division. — The  tendinous  sheaths  are  divided  into  gene- 
ral or  partial,  according  to  the  number  of  tendons  which 
they  receive. 

Situation. — The  tendinous  sheaths  are  seen  principally 
in  the  extremities,  especially  in  the  sense  of  flexion — a  dif- 


94  OF  THE  FIBROUS  SYSTEM. 

ference  which  is  owing  to  the  number  of  flexor  muscles 
being  greater  than  that  of  the  extensors.  Thus,  besides  the 
strong  sheath  which  the  flexors  of  the  fingers  have  in  com- 
mon with  each  other,  each  of  them  receives  a  proper  one, 
while  the  extensors  are  maintained  in  their  proper  place 
merely  by  some  of  the  tendinous  fibres  of  the  interoseous 
muscles. 

Form  and  arrangement. — The  sheaths  of  the  tendons 
are  so  arranged,  that  some  of  them  form  complete  canals 
for  the  passage  of  the  tendons,  while  others  form  only  a 
part,  the  other  part  being  formed  by  the  bones  which  give 
insertion  to  the  extremities  of  the  tendinous  sheaths.  In 
some  instances,  they  form  true  canals,  while  others  consti- 
tute only  a  kind  of  rings,  and  are  hence  called  annular 
ligaments.  When  these  sheaths  receive  more  than  one 
tendon,  they  are  either  simple  or  compound,  that  is,  they 
are  divided  by  fibrous  prolongations  into  as  many  canals 
as  there  are  tendons.  They  are  continuous  with  the 
aponeuroses  of  the  extremities  where  they  are  found. 
Their  internal  surface  is  lined  by  a  vaginal  synovial  pouch, 
which,  in  the  compound  sheaths,  sends  reflections  between 
the  tendons,  so  as  to  form  more  or  less  complete  septa. 

Texture. — The  tendinous  sheaths  are  of  a  very  dense 
and  compact  texture,  and  are  composed  of  transverse  or 
oblique  fibres,  which  are  more  apparent  in  some  than  in 
other  places. 

Functions. — They  give  strength  and  firmness  to  the 
tendons,  maintain  them  in  their  proper  situation,  and  di- 
rect their  force. 

§  3.     Of  the  Periosteum. 

Definition. — The  periosteum  is  the  fibrous  envelope  of 
the  bones. 

Form  and  arrangement. — This  membrane  represents 
the  form  of  the  bones  which  it  surrounds  and  covers.  It 
is  wanting  on  the  cartilaginous  surfaces  of  the  moveable 


OF  THE  FIBROUS  SYSTEM.  95 

joints  where  its  continuity  is  of  course  interrupted;  in  the 
immoveable  articulations  it  passes  without  interruption 
from  one  bone  to  the  other. — In  infancy  it  is  thick,  and 
can  be  easily  separated  from  the  bones;  while  in  the  adult 
it  is  more  firm  and  compact,  and  is  intimately  connected 
with  the  short  bones  and  the  extremities  of  the  long  ones, 
and,  in  short,  every  where,  where  they  present  a  spongy 
texture.  The  periosteum  gives  off  numerous  prolonga- 
tions which  accompany  the  vessels  that  enter  every  where 
the  spongy  substance  of  the  bones. 

Texture. — The  direction  of  the  fibres  of  the  periosteum 
is  analogous  to  that  of  the  long  and  the  short  bones;  but  its 
arrangement  is  different  in  the  flat  bones.  It  receives  a 
great  number  of  blood-vessels,  and  some  lymphatics;  and 
when  subjected  to  continued  pressure,  it  is  converted  into  a 
fibro-cartilaginous  substance. 

Differences  according  to  age. — In  the  foetus,  the  perios- 
teum is  soft  and  spongy,  moistened  by  a  gelatinous  fluid, 
and  possessed  of  but  little  vascularity.  As  we  advance  in 
years,  its  fibres  become  more*  distinct,  and  the  membrane 
'  increases  in  firmness,  consistence,  and  vascularity;  in  old 
age,  it  has  extreme  tenacity,  and  even  becomes  ossified  on 
its  internal  surface. 

Functions. — The  periosteum  defends  the  bones  which 
it  covers  from  the  impression  of  the  organs  that  move  upon 
its  surface,  and  strengthens  the  parietes  of  their  vessels. 
In  infancy,  it  unites  the  epiphyses  to  the  bodies  of  the 
bones,  and  serves  for  the  insertion  of  the  ligaments  and 
tendons,  which  subsequently  and  in  consequence  of  the  os- 
sification of  this  membrane  at  their  points  of  attachment, 
adhere  to  the  bone  itself. 

Pathological  Jlnatomy. 

Wounds  of  the  periosteum  are  followed  by  a  cicatrix 
which  resembles  it  in  texture,  and  when  a  small  portion  of 
it  has  been  raised  or  detached,  it  is  generally  reproduced. 


96  OP  THE  FIBROUS  SYSTEM. 

Inflammation  of  this  membrane  seldom  terminates  in  gan- 
grene, but  most  frequently  in  suppuration,  which  detaches 
it  from  the  bone,  and  has  a  tendency  to  produce  periostosis, 
osssification,  soft  cancer,  and  the  development  of  fungous 
growths, 

§  4.     Perichondrium. 

The  perichondrium  is  the  fibrous  membrane  which  covers 
the  non-articular  cartilages;  it  is  less  intimately  connected 
to  them,  than  the  periosteum  is  to  the  bones,  and  does  not 
send  to  them  as  many  fibrous  elongations.  It  contains 
fewer  blood-vessels  than  the  periosteum,  has  less  vitality, 
and  diners  from  it  also  in  some  of  the  characters  which  we 
have  just  pointed  out. 

§  5.     Of  the  fibrous  envelopes  of  the  brain,  the  spinal 
marrow,  and  some  other  organs. 

These  membranes  are,  1st.  The  dura  mater,  (meninx 
of  Chaussier),  a  very  dense,  and  vascular  membrane, 
composed  of  tendinous-like  fibres,  running  in  various  di- 
rections, and  situated  within  the  cranium  and  the  ver- 
tebral canal,  to  the  former  of  which  it  forms  an  internal 
peri- cranium.  It  is  intimately  united  with  the  tunica 
arachnoides,  covers  the  brain  and  spinal  marrow,  and  sends 
elongations  in  the  form  of  sheaths  upon  the  nerves  which 
pass  out  at  the  base  of  the  cranium,  and  through  the  verte- 
bral holes.  This  membrane  forms  a  number  of  folds  or 
duplicatures  within  the  cavity  of  the  cranium,  which  may 
be  distinguished  into  those  which  separate  the  different  parts 
of  the  brain,  as  the  falx  major,  the  tentorium  cerebelli,  and 
the  falx  minor;  and  into  the  sinuses  of  the  dura  mater,  or 
those  which  perform  the  offices  of  veins,  and  are  lined  by 
a  continuation  of  the  internal  membrane  of  the  veins. 

2d.  The  sclerotica,  an  opake,  white,  elastic,  fibrous 
membrane,  of  unequal  thickness,  possessed  of  little  vascu- 


OF  THE  FIBROUS  SYSTEM.  97 

larity,  and  serving  as  a  covering  to  the  eye,  determining 
its  shape  and  supporting  and  defending  the  more  delicate 
and  useful  parts  within  it. 

3d.  The  tunica  albuginea,  a  strong,  dense,  in-elastic 
membrane,  varying  in  thickness,  possessed  of  but  little 
vascularity,  and  serving  to  surround  and  defend  the  testes. 
— Under  this  head  may  also  be  included  the  fibrous  en- 
velopes of  the  ovaries. 

4th,  and  lastly,  the  fibrous  capsules  of  the  kidneys, 
which  surround  them,  and  send  prolongations  into  the 
interior  of  their  substance. 

It  remains  to  bs  remarked,  that  none  of  the  organs  which 
are  surrounded  by  coverings  of  the  non-elastic  fibrous  tis- 
sue, are  destined  to  undergo  any  temporary  changes  of 
volume,  as  are  those  which  are  surrounded  and  enveloped 
by  the  elastic  fibrous  tissue. 

§  6.   Of  the  fibro-serous  and  the  fibro-mucous  mem- 
branes. 

Every  where,  where  the  fibrous  membranes  are  found 
in  relation  with  the  serous  or  the  mucous,  they  are  so  firm- 
ly united  to  them,  that  it  is  impossible  to  separate  them  by 
dissection;  so  that  they  appear  to  form  a  single  membrane, 
fibrous  on  its  external,  and  mucous  or  serous  on  its  inter- 
nal surface.  The  pericardium  and  the  tunica  vaginalis, 
are,  in  a  part  of  their  extent,  true  fibro-serous  membranes; 
the  union  of  the  dura-mater  and  the  arachnoides  is  also  very 
intimate  every  where,  where  these  envelopes  are  applied, 
the  one  upon  the  other.  We  see  examples  of  the  fibro- 
mucous  membranes  in  the  trachea,  where  the  fibrous  tunic 
is  inseparably  united  with  the  mucous;  in  the  periosteum 
and  perichondrium,  wherever  the  internal  teguments  lie 
immediately  upon  them,  as  in  the  nasal  fossae,  the  meatus 
auditorius  externus,  the  larynx,  &c. 
14 


98  OF   THE  FIBROUS  SYSTEM- 

SECOND  DIVISION. 
Yellow  elastic  fibrous  System. 

Definition. — This  system  comprehends  a  great  number 
of  membranous,  ligamentous  parts,  &c,  formed  of  a  tissue 
analogous  to  the  preceding  in  texture,  but  differing  from 
it  by  its  great  elasticity. 

Situation. — This  tissue  is  found  in  every  part  of  the 
body,  where  it  is  necessary  that  there  should  be  a  continu- 
al or  intermittent  resistance  to  the  impression  of  weight, 
to  the  action  of  the  muscles,  &c.  In  the  human  subject, 
the  principal  organs  in  which  this  tissue  occurs,  are,  the 
yellow  ligaments  of  the  vertebrae,  the  proper  coats  of  the 
vessels,  especially  those  of  the  arteries,  the  excretory  and 
aereal  ducts,  the  covering  of  the  spleen,  and  of  the  corpora 
cavernosa.* 

Conformation. — The  fibrous  elastic  tissue  is  found  un- 
der three  forms;  1st,  under  that  of  fasciculi,  as  in  the  yel- 
low ligaments;  2d,  under  that  of  tubes,  as  in  the  vessels 
and  excretory  ducts;  and  3d,  under  that  of  membranous 
capsules,  with  interior  reticular  elongations,  as  in  the  cov- 
erings of  the  spleen,  and  the  corpora  cavernosa. 

Structure. — This  tissue  is  formed  of  fibrous  fasciculi, 
parallel  with  each  other,  or  nearly  so,  but  never  interlac- 
ed, and  easily  separable;  it  contains  little  cellular  substance 
and  but  few  vessels. 

Characters,  physical  and  chemical  properties. — In  the 
living  subject,  the  elastic  fibrous  tissue  is  firm  and  opake, 
and  of  a  white  yellowish  colour,  which  becomes  more  dis- 
tinct after  death;  it  has  less  tenacity,  and  more  extensibili- 
ty than  the  other  fibrous  tissue,  is  more  tenacious  than  the 

*  In  quadrupeds,  this  tissue  constitutes  the  ligamentum  nucha:,  or  the 
posterior  cervical  ligament,  and  the  ligament  which  is  inserted  into  the 
claws  of  some  of  the  feline  species. 


OP  THE  FIBROUS  SYSTEM.  99 

muscular,  in  the  dead  than  the  living  subject,  and  bears 
a  greater  resemblance  to  it,  than  the  preceding  tissue. 
It  contains  a  great  quantity  of  water,  upon  which  depends 
its  most  remarkable  physical  property — elasticity — by  vir- 
tue of  which,  it  immediately  recovers  its  original  state, 
when  it  has  been  distended  or  compressed.  When  this  tis- 
sue is  dried,  it  loses  half  its  weight,  and  assumes  a  cor- 
neous appearance,  but  a  few  days  maceration  is  sufficient 
to  recover  its  elasticity  and  original  characters. 

The  yellow  fibrous  tissue  resists  for  a  long  time  the  ac- 
tion of  boiling  water,  the  acids  and  alkalies;  and  macera- 
tion scarcely  produces  any  alterations. — It  is  composed  prin- 
cipally of  albumen  and  fibrin. 

Vital  properties. — This  tissue  appears  to  have  neither 
sensibility  nor  contractility. 

Functions. — The  yellow  fibrous  tissue  serves  the  pur- 
pose of  ligaments  or  envelopes  to  certain  organs,  yields  by 
its  extensibility  to  their  changes  of  volume  or  situation,  and 
recovers  its  natural  form  as  soon  as  the  cause,  which  in- 
duces these  changes,  has  ceased  to  act. 

Pathological  Jlnatomy. — The  anatomical  history  of  the 
diseases  of  this  tissue,  having  been  included  under  that  of 
the  fibrous  tissue,  properly  so  called,  we  shall  only  remark 
here,  that  this  tissue  very  seldom  ossifies,  and  that  it  has  a 
tendency  to  lose  its  elasticity  from  too  frequent,  excessive, 
or  continued  distention. 


THIRD  DIVISION. 

Fibrocartilaginous  System. 

Definition. — This  system  comprehends  those  organs, 
which,  by  their  texture  and  tenacity,  participate  in  the  cha- 
racters of  the  fibrous  tissue,  and  by  their  density  and 
whiteness  in  those  of  the  cartilages.*  , 

*  Bichat  has  placed  in  this  system  the  membraniform  cartilages  which 


100  OF   THE   FIEROIJS  SYSTEM.  *"*» 

Division. — The  fibrocartilaginous  organs  are  distin- 
guished; 1st,  into  the  inter-articular,  or  those  which  are 
free  on  both  surfaces;  2d,  into  those  which  have  one  sur- 
face free  and  the  other  adherent;  these  are  the  fibro-carti- 
lages  of  the  tendinous  sheaths  and  of  the  circumference  of 
the  articular  cavities;  3d,  into  those,  which  adhere  by  their 
two  surfaces  to  the  bones  to  which  they  serve  as  a  bond  of 
union. 

Situation,  conformation,  and  arrangement. — 1.  The 
inter-articular  fibro-cartilages,  are  situated  in  the  articula- 
tions of  the  knee,  the  inferior  maxillae,  and  the  clavicle. 
They  are  lamelliform,  free  on  their  surfaces,  connected  by 
their  borders  to  the  synovial  capsules  or  the  articular  car- 
tilages, and  sufficiently  moveable  to  adapt  themselves  to  the 
motions  of  the  joints  in  which  they  are  placed;  2,  The  fibro- 
cartilages,  adhering  by  one  of  their  surfaces,  consist,  1st, 
of  those  of  the  tendinous  sheaths,  which  facilitate  the  glid- 
ing of  the  tendons,  and  protect  them  from  the  impression 
of  the  bones;  and  2d,  of  those  which  surround  the  glenoid 
and  cotyloid  cavities;  3,  The  fibro-cartilages  which  are  ad- 
herent by  their  two  faces,  are  placed  between  the  surfaces 
of  the  bones,  to  which  they  serve  as  bonds  of  union:  these 
vary  in  form,  being  circular  in  those  which  connect  the 
bodies  of  the  vertebrae,  almost  quadrilateral  between  the 
symphysis  pubis,  &c. 

Structure. — The  fibrous  and  cartilaginous  tissues  are 
not  combined  in  the  same  proportion,  nor  disposed  in  the 
same  manner  in  every  part  of  the  fibro-cartilaginous  sys- 
tem, nor  every  where  in  the  same  fibro-cartilage.  Thus, 
the  fibrous  substance  predominates  in  the  inter-vertebral 
ligaments,  where  it  forms  concentric  layers;  it  is  less  abun- 
dant, and  consists  of  circular  fibres  where  it  surrounds  the 

are  regarded  by  Meckel,  Beclard  and  other  anatomists,  as  true  cartilages. 
We  shall  see  in  the  following  chapter,  that  this  manner  of  observing  the 
membranif'orm  cartilages  is  preferable  to  that  of  Bichat. 


OP  THE  FIBROUS  SYSTEM.  101 

glenoid  and  cotyloid  cavities;  still  less  abundant  in  the  in- 
ter-articular fibro  cartilages,  and  often  scarcely  distinguish- 
able in  the  sheaths  of  the  tendons,  where  it  is  formed  at 
the  expense  of  the  periosteum,  which  is  almost  entirely 
converted  into  cartilage.  In  general,  the  fibrous  substance 
is  more  apparent  in  proportion  as  the  fibro-cartilage  is  ex- 
amined near  its  external  surface;  and  the  cartilaginous,  in 
proportion  as  we  approach  nearer  to  the  centre  of  an  organ 
where  the  fibres  disappear.  In  some  instances  there  is 
alternately  a  layer  of  the  fibrous  tissue  and  one  of  the  car- 
tilaginous. The  fibro-cartilaginous  system,  like  the  two  of 
which  it  is  composed,  has  but  little  vascularity. 

Characters,  physical  and  chemical  properties. — The 
fibro-cartilages  are  of  a  whitish  appearance,  and  unite  to 
the  tenacity  of  the  fibrous  system,  the  elasticity  of  the  car- 
tilages. It  has  been  observed,  that  during  pregnancy,  the 
fibro-cartilages  which  unite  the  bones  of  the  pelvis  are  sen- 
sibly softened,  and  become  more  humid.  The  fibro-carti- 
lages resist,  for  a  considerable  time,  the  action  of  boiling 
water,  but  dissolve  at  last  into  gelatine. 

Vital  properties. — In  the  healthy  state,  the  fibro-carti- 
lages appear  to  have  neither  sensibility  nor  contractility. 

Differences  according  to  age. — In  infancy,  the  fibro-car- 
tilages are  soft,  and  appear  to  be  composed  principally  of 
ahomogeneous  substance, and  as  their  consistency  increases, 
their  fibres  become  distinct,  and  more  fully  developed. 
They  seldom  ossify  in  old  age. 

Functions. — The  fibro-cartilaginous  organs  differ  in  their 
uses  in  the  different  parts  of  the  body:  some  facilitate 
the  motions  of  the  tendons,  giving  them  a  point  of  attach- 
ment at  once  solid  and  elastic;  others  favour  the  mobility 
of  the  articular  surfaces  between  which  they  are  situated, 
either  as  a  kind  of  cushion,  or  as  elastic  ligaments. 

Pathological  Anatomy. 
In   consequence  of  their   small  degree  of  vitality,  the 


102  BIBLIOGRAPHY  OF  the  fibrous  system. 

fibro-cartilages  are  seldom  subject  to  diseases;  when 
wounded,  they  inflame,  and  after  a  considerable  time  they 
cicatrize  and  heal.  Inflammation  of  these  organs  is  slowin 
its  progress  and  is  characterized  by  redness,  which  is  either 
uniform  or  striated,  and  often  passes  to  a  brown  colour;  it 
often  terminates  in  the  effusion  of  a  kind  of  ichorous  matter, 
which  is  either  deposited  in  their  substance,  or  exhaled 
upon  their  external  surface.  They  seldom  ulcerate,  though 
this  has  been  observed  to  take  place.  In  many  ricketty  sub- 
jects, and  in  some  of  those  who  suffer  from  mal-conforma- 
tion  of  the  vertebral  column,  the  inter-vertebral  fibro-car- 
tilages tumify,  and  become  softened  and  engorged  with 
fluids.  Amongst  the  preternatural  fibro-cartilaginous  pro- 
ductions, we  may  cite  those  which  are  developed  in  the 
fibrous  tissue  in  consequence  of  accidental  friction,  and 
those  which  occur  in  some  cysts,  or  in  certain  tumours,  and 
cicatrices,  as  in  tubercles  of  the  lungs,  and  in  many  other 
fibrous  bodies. 

Bibliography  of  the  fibrous  System, 

Besides  the  works  already  cited,  the  reader  is  referred 
particularly  to  the  excellent  articles  by  Beclard  in  his  ad- 
ditions to  the  Anatomie  Generale  de  Bichat,  and  to  those 
in  his  own  work,  Chap.  VII.  (vas.  sys.)  p.  328,  et  seq. 
For  an  account  of  the  pathological  anatomy  of  the  fibrous 
and  fibro-cartilaginous  systems,  see  l'Histoire  Anatomique 
des  Inflammations  de  M.  le  docteur  Gendrin,  p.  322,  et  seq., 
and  the  articles  by  Laennec,  in  Dictionnaire  des  Sciences 
Medicales;  tome  XV. 


CARTILAGINOUS  SYSTEM.  103 


CHAPTER  V. 

CARTILAGINOUS  SYSTEM, 


SECTION  1. 

General  Observations. 

Definition.  — The  cartilages,  or  the  organs  which  com- 
pose this  system,  consist  of  hard  whitish  substances,  some- 
what flexible  and  elastic,  having  apparently  neither  texture 
nor  organization,  independent  of  each  other,  and  generally 
in  connexion  with  the  osseous  system. 

Division. — The  cartilages  are  divided  into  two  great 
classes;  into  those  which  are  temporary  and  those  which 
are  permanent.  These  last  are  again  subdivided  into  two 
classes;  the  first  comprehends  the  articular  cartilages,  or 
those  which  are  not  covered  by  the  perichondrium;  in 
the  second  are  included  all  those  which  receive  a  covering 
from  this  membrane,  viz.  the  membraniform  cartilages, 
the  cartilages  of  the  ribs,  the  larynx,  &c. 

Conformation  and  relations. — The  cartilaginous  or- 
gans present  a  great  variety  of  form;  some  are  long  and 
narrow,  others  thin  and  broad  and  spread  out  like  a  kind 
of  membrane;  all  are  more  or  less  flattened.  We  shall  enter 
more  into  detail  with  regard  to  their  form  in  the  following 
sections.  The  articular  cartilages  are  firmly  united  to  the 
articular  extremity  of  the  bones,  either  by  their  two  sur- 
faces, as  in  the  synarthrodial  joints,  or  by  one  only,  as  in 
the  moveable  articulations.    Those  of  the  second  subdivi- 


* 


104  CARTILAGINOUS  SYSTEM. 

sion  adhere  to  the  bones,  as  those  of  the  ribs,  the  ear,  the 
nose,  &c.  or  they  are  in  relation  with  the  soft  parts,  as  those 
of  the  larynx,  &c. 

Texture. — At  first  sight,  the  cartilaginous  tissue  appears 
to  be  composed  of  a  homogeneous  substance,  but  upon  a 
more  minute  examination,  small  fibres  may  be  discovered, 
whose  direction  varies  in  the  two  subdivisions  of  the  per- 
manent cartilages,  as  we  shall  see  when  treating  of  each  of 
them  separately.  When  macerated  for  a  long  time  in 
water,  this  tissue  exhibits  the  appearance  of  a  cellular  net- 
work: no  nerves  can  be  traced  into  it;  nor  does  it  appear 
to  have  any  blood-vessels,  unless  we  consider  as  such  the 
reddish  or  striated  appearance  which  it  sometimes  ex- 
hibits. The  cartilages  are,  nevertheless,  penetrated  by  the 
fluids  of  the  system;  this  fact,  which  the  nutrition  of  these 
organs  supposes,  is  rendered  evident  by  the  yellow  colour 
with  which  they  are  tinged  in  some  cases  of  jaundice. 

Characters,  physical  and  chemical  properties. — The 
cartilages  are  of  a  pearly  white  colour,  very  elastic  and 
smooth,  and  when  divided  into  thin  layers,  they  present 
the  semi-transparency  of  horn;  they  are  divisible  by  the 
scalpel,  and  are  the  only  substances  which  are  exceeded  by 
the  bones  in  hardness  and  density.1  The  cartilages  may  be 
greatly  distended  without  rupture  of  their  tissue;  they  con- 
tain a  great  quantity  of  water;  when  dried,  they  assume  a 
transparent,  yellowish  colour;  but  upon  exposing  them  to 
water  for  a  short  time,  they  recover  their  former  aspect: 
a  long  time  is  required  for  their  maceration,  and  when  ex- 
posed to  putrefaction,  they  yield  to  its  action  less  readily 
than  many  other  animal  substances.  When  boiled,  they 
become  brittle  and  indented,  and  the  articular  ones  are 
alone  dissolved  and  converted  into  a  kind  of  gelatine; 
while  the  others  remain  insoluble  and  afford  no  gela- 
tine. Chemical  analysis  has  hitherto  afforded  us  no  posi- 
tive data  with  regard  to  the  composition  of  the  cartilages 
of  the  human  subject.     According  to  the  experiments  of 

A 


CARTILAGINOUS  SYSTEM.  105 

Hatchett  and  Davy,  they  are  composed  of  albumen  and 
phosphate  of  lime,  and  according  to  Mr.  Allen,  of  albumen 
and  a  small  proportion  of  carbonate  of  lime.  Mr.  Gendrin 
regards  the  gelatinous  substance,  obtained  by  boiling  arti- 
cular cartilages,  as  a  compound  of  albumen,  animal  mucus 
and  phosphate  of  lime;  according  to  this  author,  the  carti- 
lages of  the  larynx  contain  gelatine,  formed  in  great  mea- 
sure of  fibrin  in  combination  with  water. 

Vital  properties. — The  cartilages  have  little  sensibility 
in  their  healthy  state,  and  their  vital  action  is  very  ob- 
scure: they  are  slowly  developed,  except  at  the  period  of 
puberty,  when  those  of  the  larynx  suddenly  increase,  and 
form  one  of  the  most  remarkable  characteristics  of  that  age. 

Differences  according  to  age. — The  cartilages  have  at 
first  the  appearance  and  consistence  of  thick  mucilage;  but 
they  gradually  increase  in  density,  until  they  at  length  ac- 
quire their  proper  degree  of  solidity.  In  adult  life,  they 
are  more  elastic  than  at  any  other  period;  in  old  age,  they 
become  more  dry,  increase  in  colour  and  opacity;  and 
sometimes,  in  consequence  of  the  greater  proportion  of 
calcareous  substance,  they  become  hard  and  ossified  either 
in  part,  or  entirely.  The  cartilages  of  the  diarthrodial 
joints  are  the  only  ones  which  are  not  subject  to  this  trans- 
formation, which  sometimes  affects  the  others  at  a  very 
early  age. 

Functions. — The  use  of  the  cartilages  is  to  facilitate  the 
motions  of  the  bones,  to  connect  them  together,  and  to 
form  the  basis  of  certain  parts,  either  in  part  or  entirely. 

Pathological  Jinatomy. 

When  the  cartilages  are  divided  without  loss  of  sub- 
stance, the  surfaces  of  the  solution  of  continuity  remain  in 
juxta-position,  but  do  not  contract  adhesions,  and  the  peri- 
chondrium alone,  when  it  exists,  cicatrizes  and  forms  an 
osseous  callus  which  closes  up  the  wound.  When  detached 

from  the  surrounding  tissues,  they  do  not  unite  with  them. 
15 


106  CARTILAGINOUS  SYSTEM. 

Inflammation  of  these  organs,  though  not  well  characteriz- 
ed, sometimes  terminates  in  ulceration,  tumefaction,  and 
softening,  and  the  development  of  lardaceous  productions, 
especially  in  some  of  the  diseases  of  the  joints.  We  shall 
speak  more  in  detail  concerning  these  alterations,  when 
treating  of  the  different  kinds  of  cartilages. 

In  some  instances,  cartilages  are  accidentally  developed 
in  the  animal  economy:  Mr.  Laennec  has  divided  them 
into  perfect  and  imperfect — a  division  which  has  been  re- 
jected by  Meckel,  who  made  his  observations  at  different 
periods  of  the  development  of  similar  productions.  The 
accidental  cartilages  occur  under  the  form  of  layers  in  the 
thickness  of  the  parietes  of  the  arteries,  the  subserous  tis- 
sue of  the  spleen,  the  lungs,  the  testicles,  &c. ;  in  irregular 
masses  in  the  substance  of  some  organs,  as  the  thyroid 
glands,  the  ovaries,  &c,  and  finally,  in  some  schirrous  and 
lardaceous  tumours  under  the  form  of  small,  flattened  bodies, 
which  are  either  attached  or  free  on  the  exterior  or  in  the 
interior  of  the  synovial  membranes,  but  seldom  in  the  se- 
rous. The  ureters,  the  vagina,  and  the  prepuce,  are  all 
sometimes  the  seat  of  a  cartilaginous  transformation;  and 
sometimes,  though  very  seldom,  even  the  bones  them- 
selves. 


section  2. 
Articular  Cartilages. 

Definition. — The  articular  cartilages  are  those  which 
cover  the  articular  surfaces  of  the  bones. 

Division. — The  articular  cartilages  are  divided  into  the 
diarthrodial  and  synarthrodia!,  or  into  those  of  the  movea- 
ble and  immoveable  articulations. 

Conformation  and  arrangement. — {a)  The  diarthro- 
dial cartilages  are  in  the  form  of  flattened  lamellae,  which 
are  more  thin  at  the  circumference  than  at  the  centre 


CARTILAGINOUS  SYSTEM.  107 

of  the  convex  articular  surfaces;  more  thick,  on  the  contra- 
ry, at  their  borders  than  at  their  centre  on  the  concave  ar- 
ticular extremities,  spread  upon  the  osseous  diarthrodial 
surfaces,  which  they  cover  in  every  part  of  their  extent, 
and  to  which  they  are  firmly  united  by  one  of  their  sur- 
faces, while  the  other  is  lined  by  the  synovial  capsule 
which  separates  it  from  the  corresponding  surface  of  the 
opposite  articular  cartilage,  (b)  In  the  immoveable  joints, 
the  articular  cartilages  are  lamelliform,  and  adhere  to  the 
bones  by  their  two  surfaces,  and  to  the  periosteum  by 
their  borders.  * 

Texture. — By  long  maceration,  the  action  of  ebullition, 
&c. ,  it  can  be  satisfactorily  shown  that  the  tissue  of  the 
articular  cartilages  is  of  a  homogeneous  nature,  and  com- 
posed of  fibres.  These  fibres  are  small,  and  are  disposed 
perpendicularly  on  the  osseous  surface  which  they  cover, 
and  to  which  they  are  very  intimately  united;  those  of  the 
diarthrodial  cartilages  appear  to  become  soft  at  their  free 
extremity,  where  the  cellular  tissue  which  enters  into  their 
composition  is  modified,  so  as  to  perform  the  office  of  the 
synovial  capsule  which  lines  the  cartilage.  The  blood- 
vessels, nerves,  and  lymphatic  vessels  of  the  articular  car- 
tilages are  so  small  as  to  elude  observation,  but  there  can 
be  no  doubt  of  their  existence,  as  is  clearly  shown  by  the 
phenomena  of  disease. 

Chemical  characters. — The  articular  cartilages  are  the 
only  ones  that  can  be  reduced  into  gelatine  by  the  action 
of  ebullition. 

Differences  according  to  age. — To  what  we  have  al- 
ready said  upon  this  subject  in  the  preceding  section,  we 
may  add  that  the  diarthrodial  cartilages  become  very  sen- 
sibly thinner  in  old  age,  and  that  they  ossify  less  readily 

*  The  synarthrodial  cartilages  of  the  bones  of  the  cranium  are  more 
thick  on  its  convex  surface  than  on  its  concave;  so  that  the  sutures  are 
less  distinguishable  on  the  interior  than  on  the  exterior  of  that  osseous 
vault. 


108  CARTILAGINOUS  SYSTEM, 

and  more  seldom  than  any  other;  and  that,  on  the  contrary , 
those  of  the  immoveable  articulations  belong;  rather  to  the 
class  of  temporary  cartilages  than  to  that  of  permanent. 

Functions. — The  articular  cartilages  counteract,  by  vir- 
tue of  their  elasticity,  the  efforts  of  compression  and  the 
shocks  which  are  experienced  by  the  articular  surfaces; 
they  facilitate,  also,  by  virtue  of  the  same  property,  the 
motions  of  the  diarthrodial  joints. 

Pathological  Anatomy. 

In  the  phlegmasia?  of  the  joints,  the  articular  cartilages 
are  sometimes  swollen  and  softened,  so  that  their  fibres  be- 
come apparent  on  their  interior  as  well  as  on  their  free  sur- 
face, which  assumes  a  velvety  appearance.  These  cartilages, 
especially  those  of  the  diarthrodial  articulations,  are  seldom 
subject  to  inflammation;  sometimes,  however,  it  takes 
place,  and  terminates  in  suppuration,  in  ulceration,  and 
the  destruction  of  the  cartilage.*  In  some  instances,  the 
articular  cartilages  are  replaced  by  a  hard,  ivory  substance, 
which,  according  to  Meckel,  consists  of  the  urate  of  soda. 

It  sometimes  happens  that  the  diarthrodial  cartilages  be- 
come thinner  than  natural — a  phenomenon  which  Mr.Laen- 
nec  has  attributed  to  the  incomplete  reproduction  of  a  part 
of  a  cartilage  that  has  been  destroyed  by  ulceration.  The 
cartilaginous  or  osseous  incrustations  which  are  sometimes 
found  in  the  articular  cartilages,  are  new  productions  which 
enter  the  joint  by  traversing  the  synovial  membrane,  and 
are  lodged  in  depressions  of  the  cartilaginous  layer.  In 
the  false  articulations  which  are  found  between  the  two 
fragments  of  a  broken  bone,  there  is  generally  a  tissue 
which  is  more  or  less  analogous  to  that  of  the  diarthrodial 
cartilages,  but  which  ought  to  be  considered  merely  as  an 
imperfect  callus. 

*  This  destruction  is  followed  by  the  union  of  the  denuded  surfaces  of 
the  bones  which  are  then  brought  in  contact,  and  constitute  tnu  anchy- 
losis.    (V.  Path.  Anat.  of  the  Oss.  Sys.  p.  167.) 


CARTILAGINOUS   SYSTEM.  109 


SECTION.    3. 

Perichondroidal  Cartilages. 

Definition. — The  perichondroidal  cartilages  are  those 
which  constitute  the  basis  of  certain  organs,  either  in  part 
or  in  whole;  are  covered  by  the  perichondrium,  and  may 
be  reduced  into  gelatine  by  the  action  of  ebullition.  These 
cartilages,  are  those  of  the  ribs,  the  larynx,  the  auricular 
canal,  the  septum  nasi;  and  those  of  the  alas  nasi,  the  eye- 
lids, the  pavilion  of  the  ear,  the  tongue,  the  epiglottis,  the 
trachea  and  bronchia,  which  Bichat  has  improperly  ar- 
ranged under  the  head  of  fibro-cartilages. 

Form  and  connexions . — The  perichondroidal  cartilages 
vary  in  form;  some,  as  the  thyroid,  &c,  are  membraniform; 
others,  as  those  of  the  ribs,  are  in  the  form  of  thick  nar- 
row bands;  while  others  again,  as  those  of  the  trachea  and 
bronchia,  represent  incomplete  rings.  In  some  instances 
they  adhere  to  the  bones  by  their  borders,  or  their  extremi- 
ties are  intimately  united  to  them  like  the  articular  car- 
tilages, as  the  cartilages  of  the  ribs,  the  septum  nasi,  &c, 
while  others  are  in  relation  only  with  the  soft  parts,  as 
those  of  the  eye-lids,  the  larynx,  and  the  trachea.  Some  of 
these  cartilages,  as  those  of  the  larynx,  form  true  articula- 
tions, and  are  united  together  by  ligamentous  capsules. — • 
For  a  more  minute  account  of  the  form  and  connexions  of 
these  organs,  the  reader  must  consult  the  works  on  de- 
scriptive anatomy. 

Texture. — (a)  The  costal  cartilages  consist  of  elliptical 
plates,  united  together  by  transverse  fibres:  according  to 
Herissant,  they  have  a  spiral  arrangement.  Whatever  it 
maybe,  it  is  certain  that  they  can  be  decomposed  into  fibres, 
and  reduced  finally  to  cellular  tissue;  but  to  analyze  the  tex- 
ture of  these  cartilages,  it  is  necessary  to  macerate  them 
for  a  long  time  in  water,  followed  by  their  desiccation  or 


110  CARTILAGINOUS  SYSTEM. 

the  action  of  the  acids.  By  maceration  and  ebullition,  the 
other  cartilages  of  this  class  may  at  first  be  reduced  to  short 
and  very  delicate  fibres,  and  afterwards  to  cellular  tissue. 
Those  of  the  eye-lids,  of  the  ear,  and  all  the  membraniform 
fibro-cartilages  of  Bichat  are  less  dense,  and  offer  less  re- 
sistance to  maceration,  &c,  than  the  other  cartilages. 
They  are  covered  by  a  thick  perichondrium,  which  sends 
fibrous  elongations  into  the  interior  of  their  substance, 
while  the  fibrous  envelope  of  the  preceding  cartilages  is 
united  to  them  merely  by  cellular  tissue. 

Physical  properties. — The  perichondro'i'dal  cartilages, 
especially  the  membraniform,  are  more  or  less  flexible,  and 
very  elastic;  they  contain  more  earthy  matter  than  the  diar- 
throdial,  and  can  not  be  resolved  into  gelatine  by  the  ac- 
tion of  boiling. 

Differences  according  to  age. — Some  of  the  perichon- 
dro'i'dal cartilages,  and  especially  those  of  the  ribs,  the 
larynx  and  the  trachea,  after  they  are  fully  developed,  be- 
come hard,  and  ossified  either  in  part,  or  in  whole,  and  ac- 
quire a  soft  and  spongy  texture  in  their  centre.  In  the  cos- 
tal cartilages,  this  normal  transformation  is  accelerated  by 
phthisis  pulmonalis,  and  in  the  larygeal,  by  phthisis  laryn- 
gitis. 

Functions. — The  cartilages,  of  which  we  are  treating, 
constitute,  either  alone  or  in  conjunction  with  the  bones, 
the  basis  of  certain  parts  of  the  body,  determine  their  form, 
and  perform  the  offices  of  bones  wherever  the  movements 
of  dilatation  and  contraction,  &c,  require  an  elastic  and 
more  or  less  flexible  structure. 

Pathological  ,/lnatomy. 

The  form  of  the  perichondro'i'dal  cartilages  is  sometimes 
altered  by  the  action  of  mechanical  agents;  thus  tumours 
of  the  neck,  such  as  goitre,  &c,  give  the  tracheal  and 
bronchial  arches  a  flattened  or  triangular  form  by  the  com- 
pression which  they  exert  upon  them. 


CARTILAGINOUS  SYSTEM.  Ill 

The  solutions  of  continuity  of  these  cartilages  are  not 
followed  by  their  cicatrization;  but  the  perichondrium 
forms  a  cartilaginous  or  osseous  ring,  which  surrounds  the 
fragments  and  maintains  them  in  contact.  This  ring  is 
smaller  in  proportion  as  the  corresponding  extremities  of 
the  fragments  are  maintained  in  apposition.  If  ossification 
of  the  cartilage  has  already  taken  place,  it  forms  a  true  cal- 
lus between  the  fractured  extremities.  (V.  Path.  Anat.  of 
the  Oss.  Syst.)— Inflammation  of  these  cartilages  ordinarily 
terminates  in  ossification. 

The  cases  of  caries  and  necrosis  that  occur  in  the  cartila- 
ginous organs,  particularly  in  the  larynx,  affect  only  those 
parts  which  are  subject  to  osseous  transformations. 

Amongst  the  small  number  of  congenital  anomalies  that 
have  hitherto  been  observed  in  these  cartilages,  we  may 
notice  the  absence  of  some  of  them,  and  particularly  those 
of  the  ribs. 

Bibliography  of  the  Cartilaginous  System. 

Besides  the  works  already  cited: 

Hirissant.  Sur  la  structure  des  cartilages  des  cotes  de 
Phomme  et  du  cheval;  dans  Mem.  de  Paris,  1748,  page 

355. 

Delassone.  Sur  l'organization  des  os;  dans  Mem.  de  Paris, 
1752,  page  253 — 258.— In  this  memoir  are  contained 
some  very  interesting  details  on  the  texture  of  the  ar- 
ticular cartilages. 

J.  G.  Haase.  De  fabrica  cartiligium,  Leipsig,  1767. 

Doerner.  De  gravioribus  quibusdam  cartiliginum  muta- 
tionibus,  Tubing.  1798. 

Cruveilhier.  Observations  sur  les  cartilages  diarthrodiaux 
et  les  maladies  des  articulations  diarthrodiales;  dans 
Jirch.  ghiir.  de.  Med.,  fevr.  1814,  pag.  161. 

Gendrin.  Hist  anatom.  des  inflammations,  torn.  I,  pag. 

322  et  seq. 


112  OF  THE  OSSEOUS  SYSTEM. 


CHAPTER  VI. 

OF  THE  OSSEOUS  SYSTEM. 


SECTION   1. 

OF  THE  BONES. 

ARTICLE  I. 

General  Observations. 

Definition. — The  osseous  system  is  composed  of  an  as- 
semblage of  hard  organic  pieces,  which  are  united  together 
in  various  ways  and  in  such  a  manner  as  to  form  a  kind  of 
frame,  which  serves  as  the  basis  upon  which  the  whole 
fabric  is  built;  determines  the  general  configuration  of  the 
body,  the  motions  of  its  several  members,  and  regulates 
its  attitudes. 

Situation. — The  bones  are  always  situated  in  the  cen- 
tre of  the  soft  parts,  under  the  teguments  and  the  muscles 
that  cover  them. 

Division. — Accordingly  as  one  or  two  of  their  dimensions 
predominate,  or  as  all  three  are  nearly  equal,  the  bones 
are  divided  into  long,  broad  and  short:  when  they  have 
the  dimensions  of  any  two  of  the  preceding  kinds,  they  are 
called  mixed.  These  varieties  differ  not  only  with  regard 
to  their  dimensions,  but  also  in  some  other  characters,  as 
we  shall  see  when  speaking  of  each  in  particular. 

Conformation. — As  the  osseous  system  presents  in  its 
whole  the  general  configuration  of  the  body,  it  is  evident 
that  that  of  the  individual  bones  themselves  presents  many 


OF  THE  OSSEOUS  SYSTEM.  113 

varieties  in  the  different  regions  in  which  they  are  situa- 
ted— a  fact  which  indicates  the  division  which  we  have  just 
established:  we  shall  revert  to  this  subject  in  the  history 
of  the  different  kinds  of  bone;  while  we  speak  here  of  the 
protuberances  and  depressions  which  are  presented  on  the 
surfaces  of  all  the  bones,  and  which  modify  their  confor- 
mation. 

1.  Of  the  eminences. — The  eminences  are  either  arti- 
cular or  non-articular:  the  first  are  incrusted  with  cartilage, 
and  enter  into  the  formation  of  the  joints;  the  second  are 
destitute  of  cartilage,  are  more  or  less  rough,  and  are  des- 
tined for  the  most  part  to  give  insertion  to  muscles,  &c. 
The  varieties  of  form,  which  are  presented  by  these  emi- 
nences, have  induced  anatomists  to  distinguish  them  into 
several  species,  known  under  the  generic  names  of  apo- 
physes, processes,  and  rami,  when  they  are  long  and  very 
salient;  by  those  of  jjrotuberances  and  tuberosities,  when 
they  are  short,  rough  and  unequal;  by  those  of  crests,  when 
they  are  very  salient,  narrow,  and  extended;  of  spines, 
when  they  are  small,  thin  and  acute;  of  lines,  when  they 
are  long  and  slightly  projecting. 

2.  Of  the  depressions. — The  depressions,  or  cavities, 
are  also  distinguished  into  articular  and  non-articular:  the 
first  only,  like  the  corresponding  eminences,  are  incrusted 
with  cartilage.  (See  History  of  the  Articul.)  The  second, 
which  will  alone  occupy  our  attention  on  the  present  occa- 
sion, are  either  external  or  internal.  The  external  cavi- 
ties are  generally  mere  depressions,  but  sometimes  they 
constitute  true  cavities:  both  present  many  varieties  of 
form;  thus,  when  the  depressions  have  a  large  and  wide 
cavity,  they  are  termed  fossae,  or  digital  impressions. 
When  the  cavities  are  deeper,  narrow  at  their  origin,  and 
wide  in  the  rest  of  their  extent,  they  are  termed  cells  or 
sinuses,  according  to  their  number  and  capacit}',  which 
are  in  an  inverse  ratio;  the  former  being  predominant  in 

the  cells;  the  latter  in  the  sinuses:  they  are  lined  by  a  mu- 
16 


114  OF  THE  OSSEOUS  SYSTEM. 

cous  membrane,  and  contain  atmospheric  air.  The  third 
class  comprehends,  under  the  names  of  furrows,  grooves, 
&c,  the  depressions  which  are  more  or  less  narrow  and 
elongated,  and  which  generally  receive  blood-vessels  and 
nerves;  in  the  fourth  class  are  included  the  foramina,  fis- 
sures and  canals,  which  pierce  through  the  substance  of  the 
bones,  and  are  more  especially  destined  to  give  passage  to 
vessels  and  nerves. 

The  osseous  eminences  and  cavities  are  formed  either  by 
a  single  bone,  or,  as  is  most  frequently  the  case,  by  the 
union  of  two  or  more  of  these  organs.  Many  of  the  bones, 
also,  present  rough,  uneven  surfaces,  which  serve  for  the 
attachment  of  muscles,  ligaments,  &c. 

Besides  the  cavities  which  communicate  on  the  exterior 
of  the  bones,  there  are  some  which  are  completely  internal, 
and  which  modify  in  a  considerable  degree,  the  interior 
conformation  of  these  organs.  On  the  internal  surface  there 
are  small  cavities  which  are  single,  and  in  the  form  of  ca- 
nals in  the  bodies  of  the  long  bones,  and  under  the  form 
of  cells,  varying  in  number,  size  and  figure,  in  all  the  other 
parts  of  the  osseous  system.  These  cavities,  which  result 
immediately  from  the  texture  of  these  organs,  are  always 
more  developed  in  the  centre  of  the  bones  than  at  their 
extremities:  they  sustain  the  marrow  and  prevent  one  part 
of  it  from  compressing  another. 

Texture. — The  bones  are  composed  of  a  nbro-lamellated 
tissue,  very  compact  at  their  exterior,  more  spongy  at 
their  interior;  this  difference  of  texture  has  induced  anato- 
mists to  distinguish  in  them  a  compact,  a  reticular,  and 
spongy  tissue.  In  the  first,  which  serves  always  as  a  co- 
vering to  the  others,  the  fibres  and  lamellae  are  applied 
upon  each  other  in  such  a  manner  as  to  give  the  bone  a 
fibrous  appearance.  The  fibres  being  very  irregular,  and 
in  juxta-position,  leave  mere  microscopic  interstices  be- 
tween them  of  the  form  of  small  canals,  being  composed 
of  lamellated  layers,  united  together  by  transverse  or  ob- 


OF  THE  OSSEOUS  SYSTEM.  115 

lique  fibrillae.  The  reticular  tissue  is  less  compact  and  con- 
stitutes the  most  internal  layers  of  the  bone.  In  the  spongy 
tissue,  the  fibres  and  lamellae  leave  small  spaces  or  cells 
between  them,  which  resemble  those  of  sponge  or  of  inflated 
cellular  tissue,  and  form  the  second  kind  of  the  small  osse- 
ous cavities  to  which  we  have  just  alluded.  Modern  re- 
searches have  ascertained  that  the  osseous  texture  is  nothing 
but  cellular  tissue,  hardened  by  its  combination  with  a  ge- 
latine-calcareous  substance,  but  which  preserves  the  inte- 
rior form  of  its  primitive  state  until  the  fat  is  deposited 
into  its  cells. 

Besides  the  osseous  tissue,  there  are  other  parts  that  en- 
ter into  the  composition  of  bones,  and  these  are:  1st,  a  fi- 
brous membrane  which  serves  as  an  external  envelope,  and 
which  has  already  been  described  under  the  name  of  peri- 
osteum (v.  page  94);  2d,  the  marrow,  or  the  adipose  tis- 
sue of  the  bones,  which  is  lodged  in  the  cells  of  the  spongy 
and  reticular  substance,  and  even  in  the  compact  tissue,  as 
well  as  in  the  large  interior  canal,  of  the  long  bones,  where 
it  is  contained  in  a  cellulo-vascular  membrane  peculiar  to 
that  canal.  The  fat  of  bones  consists,  if  not  every  where, 
at  least  in  the  most  spacious  lacunas,  of  small  spheroids  fill- 
ed with  an  oily  substance,  more  fluid  and  of  a  more  yel- 
lowish colour  than  that  of  the  general  adipose  tissue;  3d, 
blood-vessels,  which  have  been  distinguished  by  anatomists 
into  three  orders:  the  first  comprehends  the  small  arterial 
branches,  which  are  derived  from  the  vascular  net-work  of 
the  periosteum,  and  which  enter  the  microscopic  orifices, 
and  are  distributed  to  the  compact  substance.  The  second 
order  consists  of  the  vessels  which  penetrate  into  the  spongy 
substance  by  the  foramina,  which  are  observable  upon  the 
surfaces  of  the  short  and  at  the  extremities  of  the  long 
bones:  in  the  third  order  are  included  the  vessels  known 
more  particularly  under  the  name  of  nutritient,  which  tra- 
verse, without  ramifying,  the  hollow  canals  in  the  compact 
substance,  and  are  distributed  to  the  membrana  medullaris. 


116  OF  THE  OSSEOUS  SYSTEM. 

The  corresponding  veins  of  the  first  two  orders  do  not  pass 
out  at  the  orifices  which  receive  the  arteries,  while  the  ar- 
teries of  the  third  order  are  generally  accompanied  by  veins 
which  exactly  correspond  to  them  in  number  and  volume. 
The  parietes  of  the  veins  of  the  compact  and  spongy  tis- 
sues are  formed  merely  of  the  internal  membrane  of  the 
venous  system;  they  present  a  cellular  arrangement,  which 
establishes  an  analogy  between  them  and  those  which  con- 
stitute the  erectile  tissue  of  the  corpora  cavernosa,  &c, 
being  formed,  like  them,  merely  of  the  internal  mem- 
brane of  the  venous  system — a  character  which  belongs 
also  to  the  small  venous  ramifications  of  the  compact  sub- 
stance. 

As  yet,  no  lymphatic  vessels  have  been  traced  into  the 
substance  of  the  bones;  and  the  nerves,  which  accompany 
the  vessels  of  the  medullary  membranes  of  the  long  bones, 
can  not  be  discovered  in  the  osseous  tissue  itself. 

Characters,  physical  and  chemical  properties. — The 
bones  are  of  a  white,  yellowish  colour,  very  hard,  compact 
and  resisting,  possessed  of  a  very  small  degree  of  flexibili- 
ty and  elasticity,  and  susceptible  of  slow  extension,  follow- 
ed, when  the  cause  of  extension  is  removed,  by  the  return 
of  these  organs  to  their  primitive  dimensions;  (as  in  some 
of  the  osseous  cavities,  such  as  the  nasal  fossae,  the  orbit, 
&c.  which  are  sometimes  temporally  enlarged  by  the  pre- 
sence of  tumours,  and  which  regain  their  original  capacity 
as  soon  as  these  tumours  are  removed).  The  solidity  of  the 
bones  depends  upon  their  chemical  composition,  which, 
according  to  the  analysis  of  Berzelius,  consists  of  the  fol- 
lowing ingredients: — Animal  substance  reducible  into  ge- 
latine, 32.17;  insoluble  animal  substance,  1.13;  carbonate 
of  lime,  1 1.3;  phosphate  of  lime,  51.4;  fluate  of  lime,  2.00; 
phosphate  of  magnesia,  1.16;  soda,  and  phosphate  of  soda, 
1.20.  The  analysis  of  Fourcroy  and  Vauquelin  differs 
somewhat  from  the  preceding;  for,  besides  the  ingredients 
already  enumerated,  these  chemists  have  detected  the  pre- 


OF  THE  OSSEOUS  SYSTEM.  117 

sence  of  a  small  quantity  of  iron  and  silica.  The  composi- 
tion of  the  bones  varies  also  according  to  the  age  of  the 
individual,  the  state  of  health  or  disease,  and  the  kind  of 
bone  that  is  examined.  The  gelatinous  parts  of  bone  are 
extracted  slowly  by  boiling  water,  and  the  saline  part  is 
readily  decomposed  by  some  of  the  acids. 

Vital  properties. — The  bones,  in  their  healthy  state, 
possess  but  a  small  share  of  sensibility;  they  are  destitute 
of  contractility,  and  the  slowness  with  which  they  are 
formed  and  repaired,  sufficiently  proves  that  they  are  en- 
dowed with  but  a  small  degree  of  vitality. 

Mode  of  development,  and  differences  according  to 
age. — The  bones,  which  are  at  first  liquid  like  all  the  other 
parts  of  the  body,  become  gradually  gelatinous,  and  pass  suc- 
cessively (at  least  the  majority  of  them,)  into  the  cartilagin- 
ous and  fibro-cartilaginous  states,  and  from  these  into  the 
osseous.  At  the  commencement  of  embryotic  life,  the  os- 
seous system  is  merely  of  the  consistence  of  mucus,  and 
forms  an  uninterrupted  whole,  which  is  soon  after  divided 
into  a  great  number  of  parts.  Ossification  begins  about  a 
month  after  the  time  of  conception,  and  is  not  fully  com- 
pleted before  the  twelfth,  and  in  some  accessory  parts,  not 
until  the  eighteenth  year  of  age.  Ossification  does  not 
appear  to  result  uniformly  from  the  change  of  cartilage 
into  bone.  According  to  Howship,  some  parts  of  the  os- 
seous system,  such  as  the  bodies  of  the  long  bones  and  the 
broad  bones  of  the  cranium,  pass  immediately  from  the 
mucous  to  the  osseous  state.  The  formation  of  bone  is 
accompanied  by  some  very  remarkable  and  curious  pheno- 
mena: in  the  centre  of  the  temporary  cartilage,  which  is 
formed  about  two  months  after  conception,  and  which 
has  already  the  configuration  of  the  bone,  may  be  observ- 
ed small  canals,  and  vessels  which  are  lined  by  a  vascular 
membrane,  filled  at  first  with  a  viscous,  and  subsequently 
with  a  sanguineous  fluid:  the  appearance  of  this  fluid  is 


IIS  OF  THE  OSSEOUS  SYSTEM. 

soon  followed  by  that  of  the  first  osseous  point.*  The  car- 
tilage, being  injected  with  red  around  the  transformed 
part,  presents  a  homogeneous  aspect  in  proportion  as  it  is 
examined  near  its  circumference.  Ossification  thus  ex- 
tends gradually  from  within  outwards,  and  finally  termi- 
nates by  the  complete  removal  of  the  cartilage.  The  canals 
to  which  we  have  just  alluded,  being  large  at  the  com- 
mencement of  ossification,  diminish  progressively,  and  in 
proportion  as  the  process  of  ossification  is  completed:  and 
instead  of  the  homogeneous  substance  of  the  temporary 
cartilage,  there  is  a  complete  bone,  having  distinct  fibres 
and  blood-vessels. 

Though  numerous  hypotheses  have  been  advanced  in 
explanation  of  the  conversion  of  the  cartilaginous  into  the 
osseous  tissue,  our  information  of  the  nature  of  this  nutri- 
tive phenomenon  is  still  involved  in  doubt  and  uncertainty 
like  that  of  every  other  part  of  the  animal  economy;  and 
all  the  knowledge  we  possess  upon  this  subject  is,  that  the 
formation  of  bone  results  from  a  change  of  nutrition  of  the 
cellular  net-work,  in  consequence  of  the  afflux  of  blood  to 
the  cartilage,  and  by  virtue  of  which,  the  albuminous,  ho- 
mogeneous substance  is  converted  into  a  lamellated  tissue, 
composed  of  gelatino-calcareous  fibres. 

In  many  of  the  bones,  ossification  takes  place  in  several 
points;  thus,  in  some  instances,  the  two  symmetrical  halves 
of  the  azygos  bones  are  developed  separately,  coalesce 
from  the  opposite  sides,  and  are  confounded  with  each 
other  on  the  mesian  line,  as  in  the  frontal  and   inferior 

•  Every  normal  or  accidental  ossification  is  preceded  by  the  develop- 
ment of  a  small,  red,  vascular  apparatus,  in  the  point  of  the  cartilage 
or  fibro-cartilage  which  is  about  to  be  changed  into  bone.  From  the 
moment  that  ossification  takes  place  (always  in  the  centre  of  this  appa- 
ratus,) the  formation  of  vessels,  or  at  least  their  development  and  colo- 
ration, continue  to  increase,  and  in  such  a  manner  that  the  ossified  part 
is  always  separated  from  the  surrounding  parts  by  another  portion  in- 
jected with  red. 


OF  THE  OSSEOUS  SYSTEM.  119 

maxillary  bones;  while,  in  some  of  the  other  symmetrical 
bones,  as  in  the  sphenoid,  the  vertebras,  &c,  ossification 
commences  by  lateral  and  mesian  points.  The  symmetri- 
cal bones  differ  from  each  other,  both  with  regard  to  their 
number,  and  the  respective  arrangement  of  their  primitive 
osseous  points.  The  trace  of  union  of  some  parts  of  the 
same  bone,  originally  distinct,  sometimes  remains  during 
the  whole  period  of  life,  as  in  the  bones  of  the  sacrum. 
Many  of  the  articular  and  non-articular  eminences  are  form- 
ed by  distinct  points  of  ossification,  which  appear  at  very 
different  periods,  from  the  fifteenth  day  after  birth  to  the 
fifteenth  and  sixteenth  year  of  age.  These  osseous  points 
are  termed  epiphyses,  and  are  separated  from  the  bone,  by 
cartilage:  when  this  cartilage  is  converted  into  bone,  the 
epiphyses  are  changed  into  apophyses.  We  shall  endeavour 
to  express,  in  a  general  manner,  the  order  in  which  ossifi- 
cation takes  place  in  the  different  bones  of  the  skeleton, 
though  these  rules  do  not  always  obtain.  The  two  fo  1-1  ow- 
ing are  those  which  present  the  least  exceptions;  1st,  in 
the  human  subject,  the  bones  are  developed  by  degrees, 
and  run  through  the  same  stages  of  organization  as  may  be 
observed  in  the  animal  scale;  2d,  The  long  bones  are  form- 
ed before  the  flat,  and  these  before  the  short* 

*  The  following  being"  the  order  in  which  the  different  parts  of  the  skele- 
ton ossify,  we  shall  perceive  how  difficult  it  is,  after  having-  read  these 
details,  to  establish  general  rules  with  regard  to  this  point. 

Ossification  begins  at  the  end  of  the  first  month  in  the  clavicle,  and 
successively  in  the  inferior  maxilla,  femur,  tibia,  humerus,  inferior  maxilla, 
and  in  the  bones  of  the  fore-arm,  where  it  commences  about  the  thirty- 
fifth  day.  Ossification  begins  about  the  fortieth  day  in  the  fibula,  scapu- 
la, palate,  and  subsequently  in  the  central  portions  of  the  occipital  and 
frontal  bones,  the  arches  of  the  first  vertebrae,  the  ribs,  the  great  wing  of 
the  sphenoid  bone,  the  zygomatic  apophysis,  the  phalanges  of  the  fingers, 
the  bodies  of  the  middle  vertebrae,  the  nasal  and  zygomatic  bones,  the 
ilium,  metacarpal  bones;  the  phalanges  of  the  toes,  the  occipital  condyles,. 
and  theninits  basilar  portion,  the  squamous  part  of  the  temporal;  the  pa- 


120  OP  THE  OSSEOUS  SYSTEM. 

The  formation  of  bone  then  takes  place,  as  we  have  al- 
ready said,  from  within  outwards,  by  the  deposition  of  new 
osseous  substance  around  the  primitive  nucleus:  besides,  the 
periosteum  being  more  vascular  at  the  period  of  ossifica- 
tion than  at  any  other  time,  secretes  and  deposits  upon  its 
internal  surface,  osseous  layers,  which  are  united  to  the  bone 
and  add  to  its  thickness.'*     It  is  then  by  a  kind  of  juxta- 

rietal  and  the  vomer:  in  all  these  bones  ossification  commences  about  the 
middle  of  the  seventh  week.  In  the  course  of  the  same  week,  it  begins 
in  the  orbitar  process  of  the  sphenoid,  and  finally,  in  the  metatarsal  bones 
and  phalanges  of  the  toes,  and  in  the  last  joints  of  the  fingers.  During 
the  ten  succeeding  days,  ossification  commences  in  the  body  of  the  sphe- 
noid, in  those  of  the  first  sacral  vertebra:,  and  in  the  circle  of  the  tym- 
panum. About  two  months  and  a  half  after  conception,  it  is  manifested 
in  the  costiform  appendix  of  the  seventh  vertebra;  before  the  end  of  the 
third  month,  in  the  labyrinth,  and  about  the  end  of  the  third  month 
in  the  ischium,  and  internal  pterygoid  apophysis;  about  the  middle  of 
the  fourth  month,  in  the  small  bones  of  the  tympanum;  at  half  .the  term 
of  uterine  life  in  the  pubis,  os  calcis,  the  last  joints  of  the  toes,  in  the 
lateral  portions  of  the  ethmoid,  and  in  the  spongy  bones  of  the  nose; 
and  somewhat  later  in  the  first  pieces  of  the  sternum;  about  the  sixth 
month,  the  body  and  processus  dentatus  of  the  second  cervical  verte- 
bra, and  the  anterior  and  internal  masses  of  the  pelvic  or  sacral  verte- 
bra, and  subsequently,  the  astragalus  begin  to  ossify.  About  the  sev- 
enth month,  the  ethmoidal  pyramids  ossify;  then  the  crista  galli;  and 
at  the  period  of  birth,  the  first  coccygeal  vertebra,  the  os  cuboides  and 
the  anterior  arch  of  the  altas.  About  the  twelfth  month,  the  coracoid 
process,  os  magnum  and  unciforme  of  the  carpus  are  solid;  about  the  third 
year,  the  first  cuneiform  bone,  the  patella  and  the  triquetral  bones  are 
ossified;  at  the  fourth  year,  the  second  and  third  cuneiform;  about  the 
fifth,  the  scaphoid  of  the  tarsus,  the  trapezium  and  lunare;  at  eight,  the 
scaphoid  of  the  carpus  ossifies;  at  nine,  the  trapezoides,  and  finally  the 
pisiforme,  about  the  twelfth  year  of  age.  Beclard,  Anat.  Generale,  p. 
496. 

*  The  depressions  and  cavities  of  the  bones  are  determined  at  the  mo- 
ment of  ossification,  either  by  the  presence  of  some  organ  upon  which 
the  bone  is  modelled,  or  by  active  pressure,  which  is  opposed  to  the  de- 
velopment of  the  parts,  where  ossification  takes  place;  there  being  no 


\ 


OF  THE  OSSEOUS  SYSTEM.  121 

position  that  the  first  development  of  the  bones  is  effect- 
ed; but,  when  once  formed,  they  increase  by  an  interstitial 
nutrition,  which  becomes  gradually  less  active,  until  at  a 
certain  age,  (about  the  time  when  all  the  epiphyses  are 
completely  ossified  and  are  united  to  their  respective  bones,) 
it  is  no  more  than  sufficient  to  nourish  the  bone  and  keep 
up  its  preservation.*  In  the  adult,  the  nutritive  process 
continues  to  become  more  slow;  the  number  and  volume 
of  the  vessels  diminish,  and  the  bones,  beingless  pervaded 
with  blood,  become  more  dry  and  calcareous,  lose  their 
elasticity,  and  diminish  in  thickness;  hence  the  remarkable 
enlargement  of  their  interior  cavities  and  their  brittleness 
in  old  age.     In  the  female,  the  bones  retain  a  much  longer 

hollows  in  the  osseous  tissue  as  we  might  be  led  at  first  sight  to  suppose; 
the  bones  of  the  cranium  are  moulded  upon  the  brain,  the  articular  sur- 
faces upon  the  eminences  whicli  receive  them,  &c.  &c. 

*  The  knowledge  of  the  property  of  madder  in  colouring  the  bones  of 
animals  that  have  been  fed  with  it  for  a  long  time,  has  led  several  learn- 
ed physiologists  to  experiment  with  this  plant,  with  the  view  to  deter- 
mine the  mode  of  nutrition  and  growth  of  the  bones.  As  those  of  Du 
Hamel  are  the  most  interesting,  we  shall  sum  up  his  principal  results. 
The  bones  of  young  animals  that  have  been  fed  with  madder,  soon  be- 
come red,  while  those  of  old  animals,  on  the  contrary,  scarcely  undergo 
any  sensible  change,  even  after  protracted  feeding.  If  a  young  animal 
be  fed  with  madder  for  some  time,  and  then  on  ordinary  food,  the  bones 
become  red  and  white  in  alternate  layers,  which  indicates  a  juxta-position, 
and  not  an  interstitial  nutrition.  This  does,  probably,  not  take  place 
after  the  epiphyses  are  fully  united  to  the  bones.  Du  Hamel  does  not, 
however,  admit  this  juxta-position,  but  is  of  opinion,  that  the  bones  in- 
crease in  length  and  breadth,  merely  by  extension.  To  refute  this  theory, 
J.  Hunter  performed  the  following  experiment:  having  perforated  the 
two  extremities  of  the  body  of  one  of  the  long  bones  of  a  young  animal, 
it  was  killed  some  time  after,  and  upon  examination  it  was  found  that  the 
distance  which  separated  the  two  foramina,  was  the  same  as  at  the  time 
of  the  operation.  From  the  results,  therefore,  of  this  experiment,  which 
was  several  times  repeated,  Mr.  Hunter  concluded  that  the  bones  are  not 
subject  to  elongation. 

17 


122  OF  THE  OSSEOUS  SYSTEM. 

time  than  in  man,  the  characters  which  they  possessed  in 
youth. 

Functions. — The  bones  form  an  essential  part  of  the  or- 
gans of  locomotion,  performing  the  office  of  levers  for  the 
action  of  the  muscles  and  their  tendons,  which  arise  and 
are  inserted  into  them;  they  also  protect  from  external  in- 
jury the  brain,  heart,  lungs,  and  other  organs  on  which 
life  more  immediately  depends;  as  well  as  the  larger  and 
more  important  blood-vessels  and  nerves. 


ARTICLE    2. 

Of  the  long,  broad,  short,  and  mixed  bones  in  particular. 
§  1.     Of  the  long  Bones. 

Definition. — B}-  the  long  bones  we  understand  those 
elongated,  osseous  pieces,  which  contain  a  medullary  canal.* 
They  comprehend  the  humerus,  the  ulna,  and  radius;  the 
femur,  the  tibia  and  peroneus;  the  metacarpal  and  metatar- 
sal bones,  and  the  phalanges  of  the  fingers  and  the  toes. 

Situation. — All  the  long  bones  are  situated  in  the  ex- 
tremities, which  they  occupy  throughout  their  whole  ex- 
tent, with  the  exception  of  the  carpus  and  the  tarsus. 

Conformation  and  arrangement. — Thick  and  volumi- 
nous at  their  extremities,  where  we  observe  apophyses  of 
insertion,  eminences  and  articular  cavities,  the  bones  gra- 
dually diminish  and  form  imperfect  cylinders:  this  inter- 
mediate part  to  the  extremities  is  termed  their  body  or  dia- 
physis.  On  the  body  of  the  bone  are  ridges  for  the  attach- 
ment of  muscles,  generally  three  in  number,  directed  ob- 
liquely, and  in  such  a  manner  as  to  give  the  bone  a  twisted 

*  It  is  from  this  character  alone  that  we  ought  to  draw  the  generic 
name  of  the  bones  of  which  we  are  treating;  the  other  denomination  be- 
ing too  general  and  equally  applicable  to  the  bones  without  a  medullary 
canal,  as  for  instance,  those  of  the  ribs. 


OF  THE  OSSEOUS  SYSTEM.  123 

appearance.  The  long  bones  of  each  extremity,  taken  as  a 
whole,  represent  a  broken  column,  whose  pieces,  being  ar- 
ticulated in  various  ways,  as  we  shall  hereafter  see,  dimin- 
ish in  volume,  and  increase  in  number  in  proportion  as 
they  recede  from  the  trunk. 

Structure. — There  is  a  great  difference  with  regard  to 
their  interior  form,  between  the  body  and  the  extremities 
of  the  long  bones.  The  first  is  composed  of  compact  sub- 
stance, which  is  somewhat  rarefied,  and  becomes  reticular 
towards  the  centre  of  the  bone;  hence  there  is  a  canal 
which  is  lined  by  a  cellulo-vascular  membrane,  which 
sends  numerous  prolongations  into  its  interior,  supported 
in  some  instances  by  others  that  are  derived  from  the  os- 
seous substance,  and  forming,  by  their  mutual  interlace- 
ment, a  great  number  of  cells,  which  are  destined  to  receive 
the  adipose  vesicles  which  are  deposited  in  their  interior, 
or  the  marrow  properly  so  called.*  The  medullary  mem- 
brane appears  to  result  from  a  net-work  of  the  blood-ves- 
sels, lymphatics  and  nerves,  which  are  derived  from  the 
ramifications  of  those  which  enter  the  canal  through  the 
nutritient  foramina;  and  are  strengthened  and  defended 
from  injury  by  cellular  tissue.  This  membrane  is  com- 
monly considered  as  the  internal  periosteum  of  the  long 
bones:  the  quantity  and  consistence  of  the  fat  which  it  con- 
tains are  in  relative  proportion  to  the  exterior  state  of  the 
individual:  it  is  small  in  quantity,  and  almost  entirely 
aqueous  in  emaciated  persons,  while  in  those  who  enjoy  an 
ordinary  degree  of  embonpoint,  its  proportion  is  more 
considerable.  Towards  the  extremities  of  the  bone,  the 
compact  substance  greatly  diminishes,  and  is  finally  reduced- 
to  a  mere  plate  which  covers  the  spongy  substance  of  which 
the  extremities  are  composed.  The  medullary  canal  is  not 
continued  into  the  extremities;  and,  although  there  is  some- 

•  In  birds,  the  medullary  canal  is  filled  v/ith  air  which  comes  directly 
from  the  lung's. 


124  OF  THE   OSSEOUS  SYSTEM. 

times  a  small  quantity  of  marrow  in  the  cells  of  the  spongy 
substance,  there  is  never  any  distinct  membrane. 

Characters  and  physical  properties. — The  long  bones 
unite  to  the  physical  characters,  which  they  possess  in  com- 
mon with  the  rest  of  the  osseous  system,  the  property  of 
resisting,  in  a  very  great  degree,  such  forces  as  have  a  ten- 
dency to  break  them,  by  virtue  of  the  compact  texture  of 
their  bodies,  and  of  the  medullary  canal  which  occupies 
their  centre:  indeed,  in  consequence  of  this  arrangement, 
the  bones  have  a  greater  diameter,  without  increase  of  sub- 
stance, and  consequently  of  weight. 

Vital  properties. — The  osseous  part  of  the  long  bones 
affords  nothing  peculiar  with  regard  to  its  vitality;  but  the 
medullary  membrane  which  lines  their  interior  canal  is 
endowed  with  true  sensibility:  for  when  this  membrane  is 
irritated  after  the  bone  has  been  divided,  the  animal  im- 
mediately evinces  symptoms  of  pain.  It  is  also  endowed 
with  a  small  share  of  contractility,  analogous  to  that  of  the 
cellular  tissue. 

Mode  of  development  and  differences  according  to 
age. — The  long  bones  are  developed  by  three  points  of  os- 
sification; one  for  the  body  and  two  for  the  extremities. 
The  former  appears  before  the  other  two,  about  two  months 
after  conception,  without  passing  to  the  cartilaginous  state; 
there  being  already  a  hollow  which  is  occupied  by  the 
principal  nutritient  artery.  The  temporary  cartilages  hav- 
ing already  the  form  of  the  extremities  of  the  bone,  are 
united  to  the  ends  of  this  cylinder,  and  at  the  period  of 
birth,  ossification  begins  in  the  centre  of  these  terminal 
parts;  from  this  mode  of  ossification  result  the  epiphyses 
which,  as  we  have  already  seen,  remain  several  years  se- 
parated from  the  body  of  the  bone  by  means  of  cartilage. 
The  bones  gradually  increase  in  length  by  the  addition  of 
new  osseous  substance  to  the  extremities  of  the  diaphysis, 
and  by  the  union  of  this  with  the  epiphyses.  The  medul- 
lary canal,  which  is  at  first  nothing  but  a  mere  narrow  ca- 


OF  THE  OSSEOUS  SYSTEM.  125 

nal  filled  by  the  nutritient  artery,  gradually  enlarges,  and 
becomes  filled  with  a  soft  viscid  substance;  as  the  canal  in- 
creases in  size,  the  cellulo-vascular  membrane  becomes 
apparent,  which,  in  the  foetus  and  new-born  infant,  contains 
nothing  but  a  very  aqueous  fluid,  which  by  degrees  acquires 
the  properties  of  marrow. 

The  medullary  canal  continues  to  enlarge  with  the  age 
of  the  individual,  Without  encroaching  upon  the  parieles  of 
the  bones,  which  themselves  increase  on  their  external  sur- 
face; but  in  proportion  as  these  cease  to  grow,  their  parietes 
become  progressively  thinner;  so  that  in  old  age  they  form 
but  a  small  share  of  the  diameter  of  the  body  of  the  bone. 
In  proportion  also  as  the  medullary  canal  enlarges,  the 
quantity  of  marrow  increases. 

Functions. — The  long  bones  constitute  essential  parts 
in  the  articulations  of  the  extremities,  and  form  solid, 
though  flexible  columns,  capable  of  being  moved  in  various 
directions,  by  the  muscles  and  tendons  which  are  attached 
to  them. 

§  2.     Of  the  broad  or  flat  Bones. 

Definition. — The  class  of  bones  which  we  are  about  to 
describe  comprehends  those  pieces  which  vary  in  thick- 
ness, but  are  nearly  equal  in  their  length  and  breadth;  as 
the  frontal  and  parietal  bones,  the  scapula  and  os  ilium. 

Situation. — The  broad  bones  form,  in  part,  the  parietes 
of  the  cranium,  the  thorax  and  pelvis. 

Conformation. — They  are  lamelliform,  quadrilateral, 
semicircular,  &c,  more  or  less  curved,  or  contorted  in  va- 
rious directions,  so  that  the  same  side  may  be  entirely  con- 
vex or  concave,  or  alternately  the  one  and  the  other;  while 
the  opposite  sides  are  concave  and  convex.  The  flat  bones 
are  thicker  at  their  circumference  than  in  the  centre,  hav- 
ing inequalities  of  different  kinds,  which  are  more  promi- 
nent upon  their  articular  borders  than  upon  those  which 
give  attachment  to  muscles. 


126  OF  THE    OSSEOUS  SYSTEM. 

Structure. — The  flat  bones  are  uniformly  composed  of 
two  laminae  or  tables  of  solid  and  compact  substance:  in 
the  flat  bones  of  the  cranium  the  internal  layer  is  thinner 
and  more  dense  than  the  external,  and  is  hence  called  ta- 
bula vitrea.  In  some  instances  these  tables  are  in  contact 
with  each  other,  especially  in  the  centre  of  the  bone,  and  in 
others  they  are  separated  by  a  layer  of  intermediate  spongy 
substance  called  the  diploe.  This  is  exceedingly  vascular, 
having  a  great  number  of  veins,  and  containing  a  small 
quantity  of  marrow  without  any  distinct  membrane. 

Mode  of  development,  and  differences  according  to 
age. — The  broad  bones  are  developed  by  two  or  more 
points  of  ossification,  which  become  manifest  in  the  mu- 
cous substance  at  the  end  of  the  second  month  of  pregnan- 
cy, between  the  periosteum  and  the  dura  mater  for  the 
bones  of  the  cranium,  and  between  the  two  lamina?  of  the 
periosteum  for  the  other  flat  bones.  The  osseous  fibres 
issue  in  rays  from  the  centre  towards  the  circumference, 
and  finally  form  laminae  with  radiated  fibres,  which  are  still 
separated  by  the  mucous  substance.  It  has  been  observed 
by  Bichat,  that  we  ought  to  refer  the  origin  of  the  su- 
tures, which  unite  some  of  the  flat  bones  with  each  other, 
to  the  interspaces  which  are  left  at  this  period  between  the 
fibres  of  these  bones.  Soon  after  the  laminae  of  which  the 
flat  bones  are  composed,  are  united,  their  substance  be- 
comes more  conspicuous,  and  the  tables,  which  were  at  first 
confounded,  become  more  distinct  in  proportion  as  they 
increase  in  density;  leaving  between  them,  as  they  sepa- 
rate, an  intermediate  spongy  substance  formed  at  the  ex- 
pense of  the  internal  fibres  of  their  contiguous  surfaces. 
In  old  age  this  substance  is  absorbed,  the  two  tables  are 
again  brought  in  contact,  and  the  bone  becomes  sensibly 
thinner  and  weaker:  to  this  circumstance  ought  to  be  at- 
tributed the  sinking  of  the  parietal  protuberances  observa- 
ble on  the  skulls  of  old  people. 

Functions. — The  flat  bones  serve  to  defend  from  exter- 


OF  THE  OSSEOUS  SYSTEM-  127 

nal  injury  the  organs  which  are  contained  in  the  cavities 
which  they  contribute  to  form,  and  participate  in  the  func- 
tions of  locomotion,  either  by  furnishing  immoveable  ful- 
cra for  the  action  of  the  muscles,  or  in  performing  the  mo- 
tions which  these  organs  impress  upon  them. 

§  3.     Of  the  Short  Bones. 

Definition. — Under  this  class  are  comprehended  all  the 
bones  whose  length,  and  breadth,  and  thickness,  are  nearly 
of  the  same  dimensions. 

Situation. — The  short  bones  are  generally  collected  in 
groups,  and  are  situated  in  the  hand  and  foot,  &c,  and  in 
the  vertebral  column,  which  is  formed  exclusively  by  them. 

Conformation. — The  short  bones  present  too  many  ir- 
regularities to  enable  us  to  point  them  out  in  a  general  de- 
scription. Their  form  is  generally  determined  by  the 
parts  around  and  between  which  they  are  situated:  they 
are  globular,  tretroidal,  cuneiform,  cuboidal,  &c. :  all  of 
them  are  furnished  with  eminences  and  depressions,  either 
for  their  articulation  or  for  the  attachment  of  the  soft  parts. 

Structure. — The  internal  substance  of  the  short  bones 
consists  of  a  soft,  spongy,  and  areolar  texture,  which  is 
covered  and  defended  exteriorly  by  a  layer  of  firm  com- 
pact substance:  they  are  supplied  with  blood-vessels,  and 
contain  a  small  quantity  of  marrow  without  any  distinct 
membrane,  like  all  the  bones  that  have  no  medullary  canal. 

Mode  of  development,  and  differences  according  to 
age. — The  short  bones  ossify  slowly,  and  pass  from  the 
mucous  to  the  cartilaginous  state;  and  the  temporary  carti- 
lages in  which  they  are  formed  have  the  shape  and  volume 
of  the  bone  long  before  it  is  completed:  ossification  of  the 
short  bones  also  takes  place  from  the  centre  towards  the 
circumference,  and  is  attended  with  the  same  phenomena 
as  the  ossification  of  the  other  bones.  Some  of  the  short 
bones  are  developed  in  the  thickness  or  in  the  continuity 
of  some  of  the  tendons  or  ligaments,  and  pass  successively 


128  OP  THE  OSSEOUS  SYSTEM. 

from  the  fibrous  to  the  fibro-cartilaginous  state,  and  finally 
to  the  osseous.  The  patella  and  the  sesamoid  bones  are 
formed  in  this  way;  so  that  they  do  not  appear  to  be  es- 
sential parts  of  the  skeleton,  and  are  considered  by  some 
as  accidental  bones. 

Functions. — Nature  has  placed  the  short  bones  in  every 
place,  where  it  is  necessary  to  combine  a  great  degree  of 
solidity  with  that  of  mobility.  To  attain  this  double  pur- 
pose, it  was  necessary  that  they  should  be  small  and  ar- 
ranged in  groups.  Indeed,  we  know,  that  an  instrument, 
formed  of  several  pieces  which  are  firmly  united  together, 
is  more  solid  than  one  that  is  composed  of  a  single  piece, 
because  such  efforts  as  have  a  tendency  to  break  it  are  lost 
at  their  point  of  union,  and  that  the  principal  motion  of  a 
series  of  organs  occupying  a  given  extent,  is  also  much 
greater  in  proportion  as  these  organs  are  more  numerous, 
and  consequently  smaller.  The  short  bones  of  the  verte- 
bral column,  moreover,  form  a  kind  of  bony  case  for  the 
spinal  marrow,  which  is  thus  defended  from  external  in- 
jury. 

§  4.     Of  the  Mixed  Bones. 

Definition. — The  mixed  bones  are  those  which  combine 
the  form  and  characters  of  the  preceding  classes,  and  ap- 
pear to  result  from  the  union  of  the  bones  of  two  or  even 
three  of  them;  as  in  the  sphenoid,  the  ethmoid,  the  tem- 
poral, the  occipital,  the  ribs  and  the  sternum. 

Situation. — Most  of  them  belong  to  the  head  and  the 
thorax. 

Conformation. — Their  form  is  very  variable,  and  re- 
sults most  frequently  from  the  union  of  a  broad,  a  short,  and 
a  thick  part. 

Structure. — The  mixed  bones  present  the  same  struc- 
ture as  the  bones  with  which  they  are  connected.  It  is  in 
this  class  that  is  comprehended  the  hardest  and  most  com- 


OF  THE  OSSEOUS  SYSTEM.  129 

pact  osseous  part  of  the  skeleton,  viz.  the  petrous  portion 
of  the  temporal  bone. 

Mode  of  development.— -These  bones  are  formed  by- 
several  points  of  ossification,  and  possess  in  each  of  their 
respective  parts  the  mode  of  development  of  the  kind  of 
bone  with  which  they  are  connected. 

Functions. — The  mixed  bones  perform  different  func- 
tions in  the  animal  economy;  they  contribute  to  form  the 
cranium  and  the  thoracic  cavity,  surround  and  defend  the 
organs  which  they  contain,  the  encephalic  nerves  and 
some  parts  of  the  organs  of  sense,  and  give  attachment  to 
muscles. 

Pathological  Anatomy. 

The  bones  are  often  subject  to  mal-formations,  which  are 
either  congenital  or  accidental.  The  first  are  frequently 
observed  on  the  vault  of  the  cranium,  less  often  on  the  pa- 
rietes  of  the  thorax  and  abdomen,  and  seldom  in  the  ex- 
tremities. They  consist  either  in  a  defect,  or  in  an  excess 
of  development  of  the  osseous  parts  where  they  are  found, 
and  are  most  frequently  accompanied  by  congenital  ano- 
malies of  the  viscera  which  they  surround.  The  mal-for- 
mations which  are  consequent  upon  the  development  of 
the  bones,  depend  sometimes  upon  accidental  hypertrophy 
or  atrophy,  as  may  be  observed  in  some  of  the  chronic  dis- 
eases. Sometimes  also  they  result  from  inflammation  and 
swelling  of  the  periosteum,  accompanied  by  the  secretion 
of  osseous  matter,  which  is  deposited  upon  the  internal 
surface  of  that  membrane,  and  which,  uniting  with  the 
bone,  constitutes  what  is  called  external  exostosis:  this 
morbid  development  is  presented  either  under  the  form  of 
a  circumscribed  nodosity,  and  is  then  termed  node,  or  under 
that  of  a  tumour,  varying  in  extent,  and  composed  of  large 
and  superadded  layers.     When  treating  of  inflammation  of 

the  bones,  we  shall  have  occassion  to  point  out  some  of  the 
IS 


130  OF  THE  OSSEOUS  SYSTEM. 

various  alterations  which  it  is  capable  of  producing  in  the 
osseous  system. 

The  solutions  of  continuity  or  fractures  of  the  bones,  de- 
serve our  particular  attention  in  relation  to  their  mode  of 
healing.  In  the  following;  exposition  of  the  different  the- 
ories of  the  formation  of  callus  (cicatrix,)  that  have  been 
hitherto  advanced,  we  shall  see  the  great  discrepancy  in 
the  opinions  of  some  of  the  most  learned  and  experienced 
physiologists,  with  regard  to  this  highly  interesting  and 
important  subject. 

The  ancients  were  of  opinion,  that  the  extremities  of  the 
fragments  of  a  broken  bone  secreted  a  kind  of  osseous 
fluid  or  coagulable  lymph,  which  gradually  acquired  con- 
sistency, and  glued  the  extremities  together.  Haller  af- 
terwards extended  this  theory,  and  asserted  that  the  fluid, 
exhaled  by  the  extremities  ot  the  fragments  and  the  mar- 
row, was  effused  around  them,  and  became  successively 
mucous,  then  cartilaginous,  and  finally  osseous;  passing 
thus  through  all  the  different  stages  of  the  original  ossifi- 
cation. According  to  Haller  the  periosteum  is  entirely 
passive  in  the  formation  of  callus.  By  Mr.  John  Hunter 
the  formation  of  callus  is  referred  to  the  organization  and 
ossification  of  the  blood  which  is  extravasated  around  the 
broken  fragments.  In  the  present  day,  Mr.  Howship, 
embracing  the  ideas  of  M.  Dupuytren,  has  added  addi- 
tional proof  to  the  theory  of  Hunter,  and  asserts  that  the 
periosteum  becomes  cartilaginous  at  the  extremities  of 
the  fragments;  that  the  matter  of  callus  is  deposited 
successively  upon  the  surface  of  the  bone,  the  circum- 
ference of  the  extremity,  and  in  the  medullary  cavity; 
— in  a  word,  that  the  fragments  are  firmly  re-united  at 
their  exterior  parts  before  they  are  cicatrized  at  their 
extremities.  The  theory  of  Du  Hamel,  published  before 
the  time  of  Haller's,  tends  to  prove,  that  the  periosteum 
and  the  medullary  membrane,  and  sometimes  the  first  only, 
are  elongated  and  united  to  those  of  the  opposite  frag- 


or  THE  OSSEOUS  SYSTEM.  131 

ments,  and  ossified  in  such  a  manner  as  to  surround  the 
fracture  by  a  kind  of  osseous  ring.  This  re-union,  in  which, 
according  to  Du  Hamel,  the  extremities  of  the  fractured 
bone  themselves  did  not  participate,  was  regarded  by  him 
as  definite.  According  to  the  opinions  of  Bordenave,  Bi- 
chat  and  Rieherand,  fractures,  that  are  attended  by  lacera- 
tion of  the  soft  parts,  have  their  contiguous  extremities 
re-united  by  the  development  of  fleshy  granulations.  Not- 
withstanding the  theories  already  stated,  little  was  known 
with  regard  to  the  phenomena  of  osseous  cicatrization,  un- 
til the  researches  of  Dupuytren,  Breschet  and  Villerme, 
threw  new  light  upon  this  subject,  and  gave  us  more  cor- 
rect and  satisfactory  information.  We  shall  find  in  the 
ideas  of  these  gentlemen  some  of  those  of  Du  Hamel,  of 
Haller,  and  of  Howship.  According  to  the  new  theory, 
there  are  three  distinct  stages  for  the  formation  of  callus.  In 
the  first  stage,  the  small  quantity  of  blood,  that  escapes  and 
is  effused  between  the  fragments  at  the  moment  the  frac- 
ture occurs,  is  soon  followed  by  the  exhalation  of  a  viscid 
serum;  the  blood  gradually  loses  its  colour,  and  the  peri- 
osteum, the  medullary  membrane,  and  the  divided  soft 
parts  are  re-united.  The  second  stage  is  characterized  by 
inflammation  and  swelling,  accompanied  by  the  secretion 
of  coagulating  lymph  in  the  thickness  of  the  periosteum, 
and  between  it  and  the  bone:  this  matter  is  gradually  ossi- 
fied, as  well  as  the  medullary  membrane:  externally,  the 
ossification  extends  to  the  surrounding  cellular  tissue,  and 
even  to  the  muscles.  Finally,  &  provisional  callus  is  form- 
ed, a  kind  of  osseous  incrustation  on  the  surface  of  the 
contiguous  extremities,  which  may  be  compared  to  the 
osseous  rings  (virole,)  observable  in  a  great  number  of 
bones,  and  which,  in  the  long  ones,  is  completed  by  the 
formation  of  a  kind  of  osseous  pin  (eheville)  in  the  me- 
dullary cavity,  in  consequence  of  the  ossification  of  the 
medullary  membrane.  The  provisional  callus  is  nothing 
more  than  a  kind  of  solid,  retentive  apparatus,  which 
serves  to  maintain  the  fragments  in  contact.     As  soon  as 


132  OF  THE  OSSEOUS  SYSTEM. 

this  is  formed,  commences  the  third  stage — that  of  the 
permanent  callus.  Until  now  the  bone  itself  has  experi- 
enced no  sensible  changes;  but  at  this  period  the  substance 
that  was  effused  between  the  fragments  acquires  consist- 
ency and  firmness;  vessels  are  developed  which  communi- 
cate with  those  of  the  bone  and  the  periosteum,  and  finally 
ossification  is  effected,  and  the  two  extremities  are  thus 
firmly  re-united.  When  this  consolidation  is  perfect,  the 
provisional  retentive  apparatus  is  gradually  absorbed,  and 
the  medullary  canal  is  re-established.  When  the  fragments 
however,  can  not  be  maintained  in  their  natural  relations, 
after  they  have  been  brought  in  contact,  the  medullary 
canal  remains  obliterated,  and  the  exterior  callus,  instead 
of  being  merely  provisional,  becomes  permanent.  When 
the  fragments  are  not  properly  reduced,  and  maintained 
perfectly  in  contact,  they  are  re-united  by  a  kind  of  fibrous 
cicatrix,  which  generally  happens  in  fractures  of  the  patella 
and  cervix  femoris,  on  account  of  the  difficulty  of  pre- 
venting the  separation  of  the  fragments. 

Sometimes  the  extremities  of  the  fragments  are  rounded, 
becoming  firm  and  compact,  and  even  incrusted  with  car- 
tilage, and  covered  by  synovial  membrane:  hence  the  ano- 
malous articulations  which  either  prevent  or  greatly  im- 
pede the  motions  of  the  injured  parts. 

It  sometimes  happens  that  the  epiphyses  are  separated 
from  the  bones  by  mechanical  causes,  or  morbid  changes, 
such  as  inflammation;  and  in  these  cases  re-union  is  effect- 
ed in  the  same  manner  as  in  fractures.  In  cases  of  com- 
minuted fractures,  the  disorganized  parts  are  re-united  by 
callus.  Wounds  of  the  bones,  with  loss  of  substance,  are 
generally  followed  by  mortification,  and  exfoliation  of  the 
external  laminse,  and  subsequently,  by  fleshy  granulations 
and  the  restoration  of  the  exfoliated  substance.  '*     In  gene- 

*  When  the  periosteum  alone  has  been  injured,  and  the  soft  parts  are 
immediately  brought  in  contact,  re-union  often  takes  place  without  pre- 
vious exfoliation. 


OF  THE  OSSEOUS  SYSTEM.  133 

ral,  wounds  of  the  bones  are  rapidly  repaired,  and  show  the 
great  recuperative  power  of  the  osseous  tissue.  The  bones 
are  often  rendered  thin  by  the  pulsations  of  aneurismal  tu- 
mours, and  are  even  sometimes  perforated,  especially  when 
they  are  thin  and  soft  and  in  contact  with  the  tumour. 

After  amputations,  the  extremity  of  the  osseous  frag- 
ment of  the  stump  inflames,  unites  with  the  surrounding  soft 
parts,  and  is  rounded  and  covered  with  a  compact  osseous 
plate,  which  closes  up  the  mouth  of  the  medullary  canal. 
If  there  be  lesion  of  the  bone  or  the  periosteum,  beyond  the 
extremity  of  the  fragment,  slight  exfoliation  takes  place, 
but  the  cure  is  afterwards  effected  as  in  ordinary  cases. 

Primary  inflammation  of  the  bones  is  a  very  rare  disease; 
but  it  is  often  propagated  to  them  by  the  surrounding  parts, 
and  always  in  consequence  of  mechanical  injuries;  and  un- 
der these  circumstances  it  is  that  we  can  best  observe  in 
them  the  anatomical  characters  of  this  morbid  state.  When 
the  osseous  tissue  inflames,  it  swells,  becomes  more  spongy 
and  rarified  than  in  its  normal  state,  and  its  vessels  are 
highly  injected  with  blood.  These  phenomena  are  accom- 
panied by  the  secretion  of  a  gelatinous  or  red  serous  fluid, 
which  is  deposited  into  its  cells;  the  calcareous  salts  are 
gradually  absorbed,  and  the  gelatinous  substance  itself  is  evi- 
dently altered;  the  medullary  canal  disappears  in  the  neigh- 
bourhood of  the  affected  part;  and  the  membrana  medul- 
laris,  whose  interior  elongations  are  red  and  thickened,  is 
filled  in  its  interstices  with  a  fibrous  substance.  Inflam- 
mation of  the  bones  often  terminates  in  mortification 
or  necrosis:  their  compact  portions  are  more  especially 
subject  to  these  morbid  derangements,  on  account  of 
their  small  degree  of  vascularity.  The  necrosed  part  is 
uneven  and  of  a  reddish  brown  colour;  and  sometimes,  when 
mortification  succeeds  to  gangrenous  inflammation,  the  es- 
char is  brown  and  spongy,  and  emits  the  smell  that  charac- 
terizes gangrene  of  the  soft  parts:  most  frequently  the 
gelatinous  substance  of  the  bones  disappears,  and  even 


134  OF   THE  OSSEOUS  SYSTEM. 

sometimes,  the  calcareous  salts  themselves  are  decomposed. 
The  hospital  gangrene  also  extends  to  the  osseous  tissue, 
and  reduces  it  to  a  soft,  grayish,  foetid,  and  pultacious  sub- 
stance. 

In  necrosis  of  the  long  bones  there  are  some  interesting 
peculiarities,  which  are  important  to  be  understood  by  the 
surgeon,  and  which  afford  another  example  of  the  recu- 
parative  powers  of  the  tissue  of  which  we  have  been  treat- 
ing. When  the  body  of  one  of  the  long  bones  is  mortifi- 
ed, either  in  part  or  in  whole,  nature  sets  up  her  restorative 
efforts,  and  forms  around  it  another  osseous  portion  equal 
to  the  original,  and  pierced  by  several  apertures,  by  tra- 
versing which  by  means  of  a  stylet,  we  may  perceive  the 
dead  bone,  and  readily  distinguish  it  in  the  interior  of  the 
new,  by  its  mobility.*  The  sequestrum  or  dead  part  is 
discharged,  either  by  the  efforts  of  nature,  or  those  of  sur- 
gery, through  the  apertures  to  which  we  have  just  alluded: 
after  the  removal  of  the  sequestrum,  the  openings  gradual- 
ly close;  and  the  new  bone,  assuming  the  form  of  the  origi- 
nal, unites  with  its  terminal  portions,  and,  finally  exceeds 
it  in  density: — it  is  furnished  with  a  medullary  canal  and 
membrane.  In  cases  where  the  entire  thickness  of  the 
body  of  the  bone  is  necrosed,  the  restoration  is  effected  by 
the  periosteum:  in  some  instances,  the  internal  laminae 
alone  are  mortified,  and  then  the  reproduction  consists 
merely  in  an  increase  of  the  external  plates,  accompanied, 
as  in  all  other  cases  of  new  formation,  by  the  phenomena 
which  are  necessary  for  the  removal  of  the  sequestrum:  in 
necrosis  of  the  flat  and  short  bones,  and  in  the  extremities 
of  the  long  ones,  restoration  is  less  frequently  effected  than 
in  the  bodies  of  the  long  bones. 

Caries,  or  softeningand  ulceration  of  the  bones,is  another 

*  The  probe  penetrates  as  far  as  the  sequestrum  by  traversing  the  fis- 
tulous opening's,  which  nature  has  established  in  the  soft  parts,  to  favour 
its  elimination. 


OV  THE  OSSEOUS  SYSTEM.  135 

effect  of  inflammation:  it  is  characterized  by  a  softening  of 
the  osseous  tissue,  accompanied  by  a  great  degree  of  fria- 
bility, and  a  fetid  ichorous  discharge;  when  the  quantity 
of  this  fluid  is  small  and  inconsiderable,  the  disease  is  term- 
ed dry  caries — a  variety  which  seldom  occurs  but  in  the 
flat  bones  and  in  old  people.  This  ulcerative  inflammation 
attacks  more  particularly  the  spongy  bones,  so  that  the 
short  bones  are  more  liable  to  be  affected  by  it,  than 
the  others. 

When  the  inflammation  has  continued  for  some  time, 
the  oseous  tissue  becomes  swollen  and  assumes  a  lamella- 
ted  appearance;  its  fibres  separate,  and  contain  in  their  in- 
terstices a  thick  reddish  matter,  of  the  intermediate  con- 
sistence of  indurated  cellular  tissue  and  tubercles:  this  mat- 
ter is  often  converted  into  fibro-cartilage,  and  finally  into  an 
osseous  substance  constituting  a  kind  of  exostosis,  charac- 
terized by  a  simultaneousswelling  and  increase  in  the  densi- 
ty of  the  bone.  In  the  exostoses,  which  are  derived  from  the 
bone  itself,  there  are  all  the  characters,  that  are  presented  in 
the  sub-inflamed  osseous  tissue — facts  which  amply  prove 
that  these  tumours  are  the  result  of  phlegmasia?.  It  is  in- 
deed, to  inflammation  that  we  ought  to  look  for  the  cause  of 
spina-ventosa,  and  of  osteo-steatoma,  in  which  the  swell- 
ing of  the  organ  is  combined  with  the  condensation  of  its 
tissue  and  the  alteration  of  its  chemical  composition.  The 
bones  often  experience  tuberculous,  schirrous  and  cerebri- 
form  degenerations,  &c :  they  are  also  subject  to  a  re- 
markable softening,  which  arises  from  an  absorption  of  the 
earthy  part  of  the  osseous  system,  while  the  animal  matter 
remains.  When  this  disease  arises  during  the  growth  of 
the  individual,  it  constitutes  what  is  termed  rickets.  The 
bones  of  ricketty  subjects  are  of  a  reddish  appearance, 
spongy,  and  easily  cut  with  the  bistoury;  and  those  which 
are  naturally  spongy,  become  more  rarefied  and  volumi- 
nous than  the  others;  as  in  the  extremities  of  the  long  bones, 
whose  size  induces  the  vulgar  to  say  that  the  subject  is 


i 


136  OP  THE  OSSEOUS  SYSTEM. 

ricketty.  This  state  is  generally  only  temporary;  but  as 
they  acquire  their  natural  density  and  solidity,  the  bones 
retain  the  deviations  and  curvatures  which  the  pressure 
of  the  body  and  the  action  of  the  muscles  produced  dur- 
ing the  disease.  The  mollities  ossium  is  a  disease  aris- 
ing from  a  softening  of  the  bones,  and  is  generally 
attended  by  a  greater  degree  of  absorption  of  the  earthy 
salts,  than  in  the  disease  called  rickets:  it  often  supervenes 
after  the  formation  and  growth  of  the  bones  are  complete; 
when  it  is  accompanied  by  a  softening  and  fleshy  appear- 
ance of  the  osseous  tissue,  it  is  called  osteo-  sarcoma.  In  some 
instances,  the  bones  are  soft  and  brittle,  at  the  same  time 
that  they  retain  their  cellular  texture. 

All  the  tissues,  whether  normal  or  adventitious,  are  sub- 
ject to  accidental  osseous  productions:  in  the  first,  they 
result  ordinarily  from  the  effects  of  old  age,  and  are  sel- 
dom perfectly  similar  to  the  osseous  tissue.  Sometimes, 
these  productions  consist  in  mere  incrustations,  having  a 
greater  quantity  of  calcareous  matter  than  bone,  as  in  the 
arteries;  at  others,  they  consist  of  a  soft,  friable,  chalk-like 
substance,  composed  of  animal  matter,  and  earthy  salts,  as 
well  as  a  kind  of  ebony-like  substance,  as  is  sometimes 
found  to  occur  in  the  cartilages  of  the  diarthrodial  joints. 
Ossification  of  the  cartilages  and  fibro-cartilages  presents 
all  the  characters  of  the  osseous  tissue. 


SECTION  2. 

Of  the  Articulations  of  the  Bones. 

The  bones  are  connected  together  through  the  medium 
of  other  substances,  and  in  such  a  manner  as  to  form  an  en- 
tire whole  called  the  skeleton,  which  determines  the  ge- 
neral configuration  of  the  body,  and  constitutes  the  basis 
upon  which  the  whole  fabric  is  built.  The  bones  are  all 
so  admirably  arranged,  that  the  extremity  of  every  one  is 


OP  THE  OSSEOUS  SYSTEM.  137 

perfectly  adapted  to  the  end  of  the  bone,  with  which  it.  is 
connected;  and  this  connexion  is  termed  their  articula- 
tion. Every  articulation  has  its  articular  osseous  parts 
and  the  media  by  which  they  are  united.  The  articular 
surfaces,  generally,  present  inequalities,  which  determine 
the  different  kinds  of  joints,  as  well  as  the  extent  of  mo- 
tion of  the  moveable  articulations.  The  long  bones  are  ar- 
ticulated by  their  extremities,  the  broad  ones  by  their  bor- 
ders, and  the  short  ones  by  different  points  of  their  surfaces. 
All  the  bones  are  united  through  the  media  of  cartilages, 
fibro-cartilages,  or,  fibrous  ligaments.  In  consequence  of 
the  variety  of  form  of  the  articular  parts;  of  the  differences 
of  their  mode  of  union,  and  their  immobility  or  mobility, 
anatomists  distinguish  three  kinds  of  articulation;  the  first 
is  called  synarthrosis,  the  second  amphiarthrosis,  and  the 
third  diarthrosis. 

1.  Synarthrodial  Articulation. — All  the  bones  of  the 
head,  except  the  inferior  maxilla,  are  connected  by  the 
synarthrodial  articulation,  and  are  immoveable  with  regard 
to  each  other.  The  articulatory  parts  present  many  varie- 
ties as  regards  their  form  and  relations,  but  they  are  all 
united  by  an  intermediate  cartilage  which  adheres  firmly 
to  them,  and  by  the  periosteum  which  covers  it  in  its  pas- 
sage from  one  bone  to  the  other. 

In  old  age,  the  synarthrodial  articulation  is  often  oblite- 
rated by  the  immediate  continuity  of  the  two  bones  which 
it  connects,  in  consequence  of  the  ossification  of  the  synar- 
throdial cartilage.  Synarthrosis  is  divided  into  several 
varieties: 

lsjt.  Thetruesuture  is  that  kind  of  articulation  which  ex- 
ists between  the  bones  of  the  cranium,  where  the  articular 
surfaces  present  a  great  number  of  indentations,  which  cor- 
respond to  an  equal  number  of  proportionate  depressions, 
into  which  they  are  received.  Owing  to  the  trifling  dif- 
ferences which  exist  in  the  form  of  the  indentations,  this 
19 


13S  OF  THE  OSSEOUS  SYSTEM. 

suture  has  been  divided  into  three  varieties,  viz.,  the  den- 
tata,  serrata,  and  limbosa. 

2d.  The  false  or  harmonic  suture,  in  which  the  bones 
arc  connected  together  by  means  of  rough  margins;  in  this 
manner  the  bones  of  the  nose  are  connected  together. 

3d.  The  scaly  suture,  when  the  corresponding  bones 
overlap  each  other,  by  the  separation  of  their  borders, 
which  are  sharp  and  unequal,  as  in  the  temporo-pari- 
etal  articulation.  The  scaly  suture  is  said  to  be  double 
or  reciprocal  when  the  bones  do  not  correspond  by  the 
same  surfaces  throughout  their  whole  extent:  the  spheno- 
frontal articulation  is  an  example  of  this  variety. 

4th.  Schindylesis,  when  a  thin  lamella  of  bone  is  re- 
ceived into  the  narrow  furrow  of  another,  as  in  the  articu- 
lation of  the  vomer  with  the  ethmoid  and  sphenoid. 

5th.  Go?nphosis. — This  term  is  expressive  of  the  mode 
of  articulation  of  the  teeth  with  the  alveolar  cavities,  if  the 
first  be  considered  as  bones. 

2.  Jlmj)hiarthrosis. — Amphiarthrosis  is  nothing  but  a 
mixed  or  synarthrodial  articulation,  with  large,  smooth,  ar- 
ticular surfaces  connected  together  by  an  intermediate 
fibro-cartilaginous  substance,  which  adheres  firmly  to  them, 
and  has  sufficient  suppleness  and  elasticity  to  admit  of  an 
obscure  motion.  Thus  the  bodies  of  the  vertebras  are  unit- 
ed, and  move  upon  each  other  by  turning  upon  their  axes, 
or  in  bending  forwards.  The  fibrous  ligaments  which  are 
situated  around  the  amphiarthrodial  articulations  also  add 
to  their  solidity;  though,  they  are  subject  at  the  different 
periods  of  life  to  the  changes  dependant  upon  those  that 
are  experienced  by  the  intervertebral  fibro-cartilages.  (See 
Fibro-Cart.  Syst.) 

3.  Diarthrosis. — Diarthrosis  or  moveable  articulation/re- 
sults from  the  contiguity  of  osseous  surfaces  which  are  in- 
crusted  with  cartilage  and  lined  by  synovial  membrane.  This 
kind  of  connection  takes  place  between  the  bones  of  the 
extremities  and  the  trunk;  between  the  os  occipitis  and  the 


OF  THE  OSSEOUS  SYSTEM.  139 

vertebra  dentata,  and  between  the  ribs  and  the  vertebral 
column,  &c.  &c.  The  diarthrodial  surfaces  are  sometimes 
plain,  more  frequently  convex  or  concave,  or  both  at  the 
same  time;  but  their  configuration  is  always  such  that  they 
adapt  themselves  readily  to  their  corresponding  parts. 
When  the  convex  eminences  stand  out  in  a  roundish  ball 
and  constitute  the  entire  articular  surface,  they  are  termed 
heads;  when  they  are  rounded,  elongated  and  flattened, 
they  obtain  the  appellation  of  condyles.  When  the  heads 
and  condyles  rise  narrow,  and  then  become  larger,  the  nar- 
row or  small  part  is  termed  cervix  or  neck,  as  in  those  of 
the  femur  and  humerus. — When  the  depressions  are  deep, 
are  more  or  less  concave,  and  constitute  the  entire  ar- 
tioular  surface,  they  are  denominated  cotyloid  and  gle- 
noid cavities:  sometimes  they  are  designated  by  the  names 
of  pulleys  or  trochlea.  The  diarthrodial  articulations  are 
connected  by  means  of  fibrous  ligaments,  which  are  gene- 
rally attached  around  their  circumference,  and  sometimes 
to  their  centre,  and  always  in  such  a  manner  as  to  admit 
or  prevent  different  kinds  of  motion.  The  firmness  of  the 
diarthrodial  joints  is  less  than  in  the  other  classes  of  articu- 
lations, and  is  generally  in  an  inverse  ratio  to  their  mo- 
bility. Diarthrosis  is  sub-divided  into  several  species,  which 
differ  from  each  other  by  the  form  of  their  articular  sur- 
faces, their  means  of  union  and  their  quantity  of  motion. 

1st.  Planiform  Diarthrosis*  is  the  articulation  where 
the  articular  surfaces  are  nearly  plain:  are  connected  by 
strong  and  firm  ligaments,  and  are  susceptible  of  vague, 
but  obscure  motions,  as  in  the  junction  of  the  ossa  cunei- 
formia  with  the  os  naviculare;  of  the  articular  processes  of 
the  vertebrae,  &c. 

2d.  Jirthrodia. — When  the  articular  surfaces  are  more 
round,  less  firmly  united,  and  susceptible  of  more  extensive 
motions  than  in  the  preceding. 

*  The  amphiarthrosis  of  Meckel  and  some  other  anatomists. 


140  OF  THE  OSSEOUS  SYSTEM. 

3d.  Enarthrosis,  when  a  large  head  is  received  into 
a  deep  cavity,  and  is  maintained  there  by  a  capsular  liga- 
ment: this  species  of  union  admits  of  motion  to  all  sides. 

4th.  Lateral  ginglymus. — When  the  articular  surfaces 
are  convex  in  the  one  and  concave  in  the  other,  and  have  a 
part  of  their  circumference  formed  by  an  osseous  cylinder, 
and  the  other  by  a  ligament;  as  in  the  articulation  of  the 
radius  with  the  ulna. 

5th.  Angular  ginglymus,  or  ginglymus,  properly  so 
called. — In  this  articulation  the  surfaces  present  eminences 
and  depressions,  by  means  of  which  they  move  the  one 
upon  the  other;  and  where,  by  the  arrangement  of  these 
projections  and  the  ligaments  which  connect  the  joint,  the 
motions  are  confined  to  flexion  and  extension,  as  in  the  ar- 
ticulations of  the  elbow  and  the  knee. 

Pathological  Anatomy. 

The  diarthrodial  articular  surfaces  are  often  displaced  in 
consequence  of  such  efforts  as  have  a  tendency  to  extend 
or  rupture  the  ligaments  which  connect  them:  these  dis- 
placements are  termed  luxations;  and,  when  they  super- 
vene in  consequence  of  organic  alterations  of  the  ligaments, 
they  receive  the  appellation  of  spontaneous.  The  articu- 
lations are  more  subject  to  these  displacements  in  propor- 
tion as  they  are  more  moveable,  and  their  articular  surfaces 
are  smaller,  and  less  intimately  connected. 

Besides  the  accidental  articulations  which  are  sometimes 
established,  as  we  have  already  seen  between  the  two  frag- 
ments of  a  broken  bone,  there  are  others,  which  are  termed 
supplementary ,  and  which  are  consequent  upon  irreduci- 
ble luxations:  thus,  when  the  articular  head  of  a  bone  is 
removed  from  its  cavity,  it  is  applied  against  another  bone, 
and  produces  a  depression  whose  circumference  is  strength- 
ened by  a  fibro-cartilaginous  or  osseous  border,  while  its 
bottom  is  lined  by  a  substance  analogous  to  fibro-cartilage: 
— in  fact,  we  generally  find  these  kinds  of  articulation  pos^ 


OF  THE  OSSEOUS  SYSTEM.  141 

sessed  of  fibrous  and  capsular  ligaments,  &c,  and  of  syno- 
vial membranes.  The  natural  cavity  becomes  obliterat- 
ed, and  assumes  the  form  which  it  would  have  receiv- 
ed originally  from  the  free  development  of  all  its  os- 
seous points:  it  is  in  this  manner  that  the  cotyloid  cavity, 
which  is  developed  by  three  points  of  ossification,  becomes 
triangular  after  the  complete  displacement  of  the  head  of 
the  os  femoris. 

In  some  instances  the  synarthrodial  articulations  become 
swollen  and  relaxed:  it  is  in  this  manner  that  the  symphy- 
sis pubis  is  separated  during  the  last  stages  of  pregnancy, 
in  consequence  of  the  swelling  and  softening  of  the  inter- 
mediate fibro-cartilage.  *  In  some  cases  this  separation  of 
the  articular  surfaces  amounts  to  a  considerable  extent,  as 
is  observed  in  some  of  those  cases  which  result  from  hy- 
drocephalus and  the  effects  of  external  injury. 

The  bones  are  sometimes  firmly  articulated  together, 
either  in  consequence  of  acquired  stiffness  and  rigidity, 
and  the  ossification  of  the  connecting  ligaments;  or  in  con- 
sequence of  adhesions  between  the  contiguous  parts  of  the 
synovial  membrane;  or  in  consequence  of  the  synovial 
membrane,  and  cartilages  of  the  articulation  having  been 
destroyed  by  inflammation  or  some  other  cause,  the  spongy 
extremities  of  the  bones  are  brought  in  contact,  and  are 
united  with  each  other:  in  the  last  case,  which  constitutes 
what  surgeons  have  called  true  anchylosis,  the  motion  of 
the  joint  is  completely  destroyed,  while,  in  the  preceding, 

*  This  separation  of  the  pubes  being-  of  very  rare  occurrence  in  the 
human  subject,  should  by  no  means  be  regarded  as  a  provision  of  nature 
intended  to  facilitate  the  delivery  of  the  female;  but  as  purely  accidental, 
and  as  a  consequence  of  some  morbid  derangement  of  the  intermediate 
fibro-cartilage. 

In  some  animals,  however,  as  the  Guinea  pig,  this  separation  of  the 
bones  of  the  pelvis  during  the  latter  stages  of  pregnancy,  does  actually 
take  place,  and  seems  to  be  an  operation  of  nature  intended  to  facilitate 
the  parturient  efforts. — S.  D.  G. 


142  OF  THE  OSSEOUS  SYSTEM. 

which  constitute  false  anchylosis,  the  motion  is  always 
less  than  in  the  natural  state,  and  is  also,  sometimes,  totally 
destroyed.  The  articulations  of  the  elbow  and  the  knee 
are  more  frequently  affected  with  anchylosis  than  any 
other  joints  in  the  body. 

The  diseases  known  under  the  name  of  white-swelling, 
depend  most  frequently  upon  chronic  inflammation,  and 
affect,  either  alone  or  simultaneously,  both  the  soft  as  well 
as  the  hard  parts  of  the  articulations. 

Bibliography  of  the  Osseous  System. 

Besides  the  works  already  quoted: 

Malpighi.   De  ossium  structura  in  op.  posthum. 

B.  S.  Jllbinus.  De  constructione  ossium,  in  annotat.  Acad., 
Lib.  VII,  cap.  17. 

Delasone.  Memoire  sur  l'organ.  des  os;  dans  les  Me- 
moires  de  l'Acad.  royale  des  sciences.  Paris,  1751. 

J.  G.  Courtial,  J.  L.  Petit  et  Limery.  Description  ex- 
acte  des  os,  comprise  en  trois  traites. 

j3.  Scarpa.  De  Penitiori  ossium  structura  commentarius. 
Lips.,  1795,  Paris,  1804. 

V.  Malacarne.    Auetuarium  obs.  et  icon,  ad  osteol.  et  os- 
teopath. Lugduwigii  et  Scarpa?;  Patav.  1801. 
On  Osteogeny  consult  the  following: 

H.  Eysson.  De  oss.  infant,  cui  tractatui  annexus  est  V. 
Coiter  ossium  infantis  historia.  Groning.,  1659.  Th. 
Kerkring.  Osteogenic  foetus.  Lugd.-Bat,  1717.  Albi- 
nus.  Annot.  Acad.,  lib.  VI,  VII. — Id.  Icones  oss.  foetus 
hum.  accedit  osteogenic  brevis  historia.  Lugd.-Batav. 
1737. — Duhamel,  Mem.  de  l'Acad.  royale  des  sciences, 
ann.  1739 — 41 — 43 — 46. — Haller,  experimenta  de  oss. 
formatione,  in  op.  min.II. — Hirissant,  Mem.  de  l'Acad. 
royale  des  Sciences;  1768. — Biclard,  Mem.  sur  l'osteose, 
dans  le  Nouv.  Journ.  de  med.,  vol.  IV,  1S19. — Serres, 
Des  lois  de  l'Osteogenie;  analyse  des  travaux  de  l'Acad. 
royale  des  Sciences,  ann.  IS19. — Dutrochet,  observa- 


OF  THE  OSSEOUS  SYSTEM.  143 

tions  sur  l'Osteogenie,  dans  le  Journ.  de  physique,  sept. 

1822. 

On  the  history  of  Callus,  consult, 

Duhamel.  Memoires  de  PAcad.  royale  des  Sciences;  Paris, 
1741. — P.  Camper,  Observat,  circa  callum  ossium  frac- 
tor.;  in  Essay,  and  obs.  phys.  and  litter.,  vol.  III.  Edimb., 
1771. — Bonn,  de  ossium  Callo,  etc.;  Amstel.  1783. — 
Macdonald.  De  Necrosi  et  Callo;  Edimb.  1799. — Bres- 
chetf  quelques  recherches  historiques  et  experimentales 
sur  le  cal;  Paris,  1819. — J.  Sanson,  Expose  de  la  doc- 
trine de  M.  Dupuytren  sur  le  cal;  dans  le  Journal  univ. 
des  Sciences  medic,  tome  XX,  p.  131. 
On  the  pathological  anatomy  of  the  bones,  consult: 

Tenon.  Trois  memoires  sur  Pexfol.  des  os,  in  Mem.  et  ob- 
serv.  sur  Fanatomie,  la  pathologie  et  la  chirurgie,  etc. 
Paris,  1816. 

J.  L.  Bracket.  Mem.  de  Physiol,  pathol.,  sur  ce  que  devi- 
ent  le  fragment  de  l'os  apres  une  amputation;  in  Bull,  de 
la  Soc.  medic,  d'emul.  de  Paris,  1822. 

Chopart  et  Robert.  De  Necrosi  ossium  theses  anat.-chir. ; 
Paris,  1765. — Troja,  de  nov.  oss.  Paris,  1775. — Char- 
meil,  de  la  Regeneration  des  os.  Metz.  1821. 

Reichel.  De  Epiphysium  ab  ossium  diaphysi  diductione. 
Lips.,  1769. 

Jl.  Bonn.  Descriptio  thesauri  ossium  morbosorum  Hoviani. 
Amstel.  1783. — Sandifort,  de  ossibus  di  verso  mo  do  a 
solita  conformatione  abludentibus;  in  obs.  anat.  path., 
lib.  Ill  et  IV.  Lugd.-Batav.,  1777—81. 
The  following  works  on  accidental  ossification  may  be 

consulted  with  much  advantage: 

J.  H.  Van  Heckern.  De  Osteogeni  prseternaturali;  Lugdu- 
ni-Batav.,  1797. — P.  Bayer,  Mem.  sur  Possification 
morbide;  dans  les  Arch.  gen.  de  medec,  tome  I;  Paris, 
1823. 


144  OF  THE  NERVOUS  SYSTEM. 


CHAPTER  VII. 

OF  THE  NERVOUS  SYSTEM. 


SECTION  1. 

General  Observations. 

Definition. — The  nervous  system  is  an  assemblage  of 
organs  which  are  continuous  with  each  other,  are  formed 
by  one  of  the  secondary  elements  of  the  animal  organiza- 
tion— the  nervous  substance;  and  are  composed,  first,  of 
masses  or  ganglia  of  different  sizes,  and  secondly  of  fasciculi 
and  cords;  some  of  which  establish  communications  between 
the  different  masses,  while  others  extend  from  them  to  the 
different  parts  of  the  body. 

Division. — From  remote  ages  to  the  present  day,  anato- 
mists have  regarded  the  nervous  system  as  composed:  1st, 
of  a  central  unique  part — the  spinal  marrow,  according  to 
Praxagoras  and  Bartholine,  and  the  brain  according  to  Ga- 
len and  most  of  his  successors;  and  2d,  of  prolongations, 
by  which  they  understood  the  nerves  and  all  the  other  parts 
of  the  nervous  system.  Bichat,  in  unfolding  the  theories 
of  Winslow  and  Reil,  established  the  distinction  of  two 
nervous  systems:  the  one,  which  he  called  the  nervous  sys- 
tem of  animal  life,  consists  of  the  spinal  marrow,  the 
brain  and  the  nerves  which  are  given  off  by  them;  the 
other,  termed  the  nervous  system  of  organic  life,  com- 
prehends the  ganglia  and  the  nerves  which  form  the  great 
sympathetic  or  trisplanchnic  nerve.    With  regard  to  the 


OP  THE  NERVOUS  SYSTEM.  145 

latter,  Bichat  has  proved  that  it  does  not  consist  of  a  sin- 
gle system,  but  of  a  combination  of  small  distinct  sys- 
tems, communicating  together,  and  with  the  great  cerebro- 
spinal system.  Thus,  Mr.  Gall  asserts,  that  the  encepha- 
lon  and  spinal  marrow  are  an  assemblage  of  ganglia  or  in- 
dependent nervous  systems,  united  by  filaments  of  commu- 
nication, and  susceptible  of  being  brought  under  three 
groups.  The  first  comprehends  the  nervous  apparatus  of  the 
voluntary  motions  and  of  the  tactile  sensations,  or  those 
which  form  the  spinal  marrow;  the  second  consists  of  the 
nervous  apparatus  of  sense,  comprehended  under  the  name 
of  medulla  oblongata,  and  the  third,  of  the  cerebrum  and 
cerebellum,  or  those  of  the  faculties  of  the  mind.  A  fourth 
group,  composed  of  the  ganglia  and  the  trisplanchnic 
nerves,  completes  the  grand  nervous  apparatus. 

The  plurality  of  the  nervous  system  is  generally  admit- 
ted at  the  present  day;  but  many  anatomists,  in  adopting 
this  capital  doctrine,  have  modified  its  application,  and 
especially  M.  de  Blainville,  who,  founding  his  opinion  up- 
on profound  study  of  comparative  anatomy,  has  defined 
the  nervous  system,  considered  with  regard  to  the  whole 
scale  of  animal  beings,  to  be  "  a  number  of  ganglia  of  differ- 
ent sizes,  each  of  which  sending  off  nerves,  some  to  be  dis- 
tributed to  the  organ  which  it  is  to  animate  and  endow 
with  its  appropriate  life,  and  others  to  communicate  with 
the  other  ganglia  and  the  central  ganglion  (when  it  exists) 
to  establish  its  general  life."  The  central  ganglion  exists 
only  in  the  higher  classes  of  animals,  and  establishes,  in  the 
most  complete  manner,  the  individuality  of  being.  M. 
de  Blainville,  in  applying  these  ideas  to  the  nervous  sys- 
tem of  man,  represents  it  as  being  composed  of  a  central 
part — the  spinal  marrow — at  the  extremities  and  upon  the 
sides  of  which  are  placed  ganglia  that  perform  entirely  dif- 
ferent functions.  At  its  superior  extremity  and  on  the  me- 
sian  line,  there  are  seven  ganglia  composing  the  encephalic 

mass,  and  being  subservient,  some  to  the  intellectual  facul- 
20 


1  J:i  OK  THE    NERVOUS    SYSTEM. 

ties;  others  to  the  senses,  the  partial  motions  of  the  head, 
and  to  the  functions  of  respiration  and  digestion.  On  each 
side  of  the  spinal  marrow  is  another  set  of  ganglia  which 
give  origin  to  the  spinal  nerves: — finally,  in  the  splanch- 
nic cavities  are  the  ganglia  which  are  subservient  to  the 
functions  of  nutrition,  and  are  situated  near  the  organs  to 
which  they  distribute  their  nerves;  these  ganglia  are,  the 
cardiac  ganglion  in  the  thorax,  and  the  semi-lunar  plexus 
in  the  abdomen.  The  trisplanchnic  holds  the  same  cha- 
racter here  as  was  assigned  to  it  before  the  time  of  Bichat, 
being  an  intermediate  nerve  to  all  these  apparatus,  and  des- 
tined to  establish  communications  between  them,  and  in  a 
word,  to  be  a  true  sympathetic  nerve. 

We  repeat  here,  that  the  doctrine  of  the  plurality  of  the 
nervous  system  is  generally  admitted  in  the  present  day, 
and  that  authors  differ  only  in  regard  to  the  application  of 
this  capital  idea.  The  manner  in  which  M.  de  Blainville 
regards  the  grand  apparatus  of  which  we  are  treating,  is 
undoubtedly  that  which  is  the  most  expressive  of  the  ge- 
neral laws  of  organization.  Although  the  ideas  of  this 
anatomist  are  not  as  yet  generally  adopted,  it  becomes  us, 
in  a  work  of  this  kind,  to  adopt  the  division  of  the  nervous 
system  into  the  cerebrospinal  and  the  trisplanchnic,  a  di- 
vision, which  will  at  once  facilitate  the  description  of  this 
system,  and  enable  us  to  give  an  account  of  the  different 
opinions  of  the  physiologists  that  have  written  upon  this 
subject. 

Situation. — The  nervous  system  is  spread  throughout 
every  region  of  the  body:  its  central  parts  are  situated  in- 
teriorly, while  its  large  cords  are  more  superficial,  and  ap- 
proach nearer  towards  the  periphery  in  proportion  as  they 
ramify:  we  shall  have  occasion  to  see,  however,  in  a  sub- 
sequent part  of  this  work,  that  there  are  some  important 
differences  with  regard  to  the  situation  of  the  two  divisions 
of  the  nervous  system. 

Form  and  general  arrangement. — The  nervous  sys- 


OF  THE  NERVOUS  SYSTEM.  147 

tern  may  be  represented  as  a  grand  net-work,  whose  fila- 
ments, being  interrupted  by  the  small  ganglia  in  the  dif- 
ferent regions  of  the  body,  and  united  together  by  fre- 
quent communications,  extend  from  the  periphery  of  the 
body  to  the  brain  and  spinal  marrow,  diminishing  in  num- 
ber, and  acquiring,  generally,  a  larger  volume,  and  a  more 
completely  symmetrical  arrangement  in  the  two  lateral 
halves  of  the  body:  this  arrangement  is  more  perfect  in  the 
brain  and  spinal  marrow  than  irPany  other  part  of  the  ner- 
vous system. 

Texture. — The  nervous  system  is  far  from  having  the 
same  organization  in  every  part,  notwithstanding  in  this 
respect  it  presents  the  same  common  characters.  Every 
part  is  formed  of  a  peculiar  substance  called  the  nervous 
fibre,  which  has  been  regarded  by  M.  de  Blainville  as  a 
secondary  element,  resulting  from  the  modification  of  the 
primary  or  cellular  element  of  our  bodies.  This  nervous 
substance  is  presented  under  two  principal  aspects,  which 
has  led  to  the  distinction  into  the  white  and  gray  sub- 
stance. We  shall  presently  see  that  this  distinction  does 
not  merely  rest  upon  the  difference  of  colour  indicated  by 
these  denominations. 

1.  White  substance. — The  white  substance  of  the  ner- 
vous system  forms  a  continuous  whole,  and  is  generally 
surrounded  by  the  gray  substance;  but  this  is  not  the  case 
everywhere,  as  the  term  medullary,  which  is  also  some- 
times used  to  designate  it,  would  appear  to  indicate.  If 
its  consistence  be  increased  by  immersing  it  in  alkohol,  or 
in  weak  solutions  of  the  nitric  or  muriatic  acids,  upon  di- 
viding it,  it  will  exhibit  a  very  remarkable  fibrous  struc- 
ture, apparent  in  some  parts,  as  in  the  nerves  without  pre- 
vious preparation.  The  fibres  are  disposed  in  parallel  or 
oblique  fasciculi,  which  can  be  readily  separated  into  capilli- 
form  fibrilke;  but  the  mechanical  division  can  not  be  carri- 
ed so  far  as  to  enable  us  to  say  whether  these  filaments, 
which  are  very  intimately  united  together,  are  themselves 


14S  OF  THE  NERVOUS  SYSTEM. 

composed  of  other  still  more  minute  fibrillae.  The  white 
substance  is  plentifully  supplied  with  blood-vessels,  but  not 
so  much  so  as  the  gray. 

2.  Gray  substance. — The  gray  substance  is  generally 
situated  externally  to  the  white;  so  that  it  is  often  called 
cortical — a  term  which  is  by  no  means  always  applicable, 
as  we  shall  see  in  the  next  section.  It  does  not,  like  the 
white  substance,  form  a  continuous  whole;  but  is  always 
found  in  insulated  portions;  This  substance  occurs  at  the 
central  extremities  or  points  of  origin  of  the  nerves,  and  is 
there  more  abundant  in  proportion  as  the  nerves  are  larger 
and  more  numerous,  as  in  the  superior  part  of  the  brachial 
plexus:  it  is  found,  also,  every  where  where  the  white  sub- 
stance is  most  abundant  and  more  fully  developed.  From 
this  disposition,  many  physiologists  have  inferred  that 
the  gray  substance  produces  the  other,  and  is  the  matrix 
of  all  the  nerves.  If  this  were  true,  the  appearance  of 
the  first  would  necessarily  precede  that  of  the  second, 
which  is  not  the  case,  as  we  shall  presently  see.  The 
fibrous  texture  of  the  gray  substance  being  difficult  to  be 
distinguished,  even  when  prepared  as  we  shall  hereafter 
direct,  is  not  admitted  by  all  anatomists,  though  its  exist- 
ence does  not  appear  to  be  doubted  at  the  present  day,  at 
least  not  in  the  encephalo-rachidian  mass.  The  gray  sub- 
stance is  generally  very  vascular;  but  variously  in  the  dif- 
ferent parts  of  the  system. 

Examined  with  the  microscope,  the  nervous  substance 
appears  to  be  composed  of  small,  semi-transparent  globules, 
connected  together  by  a  viscid  substance,  irregularly  dis- 
posed according  to  some,  (as  in  the  brain;)  and  according 
to  others,  in  linear  orders,  (as  in  the  nerves,)  so  as  to  form 
extremely  delicate  fibres.  Anatomists  are  not  perfectly 
agreed  as  regards  the  volume  of  these  globules;  some  assert 
that  they  differ  in  the  different  parts  of  the  nervous  system, 
and  agree  to  locate  the  largest  in  the  encephalon;  while 
others,  equally  positive,  affirm  that  their  diameter  is  every- 


OF  THE  NERVOUS  SYSTEM.  149 

where  the  same.  According  to  the  late  researches  of  M. 
H.  M.  Edwards,  their  diameter  is  equivalent  to  1-3000  part 
of  an  inch.  As  to  the  nature  of  the  globules,  the  Wenzells, 
who  have  made  a  great  number  of  observations,  regard  them 
as  vesicles  containing  a  white  or  grayish  substance,  accord- 
ing to  the  parts  in  which  they  are  situated;  but  all  our 
knowledge  upon  this  subject  is  still  involved  in  doubts  and 
hypotheses.  The  globules  appear  to  be  connected  together 
by  extremely  delicate  cellular  tissue,  which  also  connects, 
and  in  a  very  intimate  manner,  the  small  delicate  fibres 
which  result  from  their  linear  disposition.  The  cellular 
tissue,  which  is  more  compact  on  the  surface  than  in  the 
interior  of  the  nervous  organs,  forms  a  thin  membranous 
layer,  having  different  names,  and  varying  in  different  parts, 
as  we  shall  have  occasion  to  point  out  in  the  following  sec- 
tions. This  membrane  is  exceedingly  vascular,  and  the 
vessels  which  are  distributed  upon  it,  penetrate  the  nerv- 
ous substance,  and  are,  as  we  have  already  said,  more  nu- 
merous in  the  gray  than  in  the  white  substance.  The 
nervous  system  appears  to  be  destitute  of  lymphatic  ves- 
sels. 

Characters,  physical  and  chemical  properties.  — The 
nervous  organs  are  very  excellent  conductors  of  the  elec- 
tric fluid.  The  two  substances  do  not  everywhere  pre- 
sent the  same  shades  of  their  respective  colours;  the  grayish 
substance,  especially,  varies  so  much,  that  in  some  places 
it  is  yellowish,  ash-coloured,  and  even  black;  these  differ- 
ences of  colour,  however,  depend  uniformly  upon  the  de- 
gree of  vascularity  of  the  part.  The  consistence  of  the 
medullary  substance  is  by  no  means  the  same  in  every 
part  of  the  nervous  system;  but  it  is  always  in  relative  pro- 
portion to  that  of  the  cortical:  both,  but  especially  the 
medullary  substance,  are  slightly  elastic,  retractile,  and 
more  resisting  in  the  direction  of  their  fibres  than  in  any 
other.  When  macerated,  the  nervous  substance  resists  for 
a  long  time  the  action  of  water,   and  its  first  effect  is  a 


150  OF  THE  NERVOUS  SYSTEM. 

softening  and  slight  discoloration  of  the  cortical  substance. 
The  effects  of  the  dilute  acids  and  of  alkohol,  upon  the 
cortical  and  medullary  substances,  have  been  already 
pointed  out.  By  desiccation  the  former  is  rendered  brit- 
tle and  pulverizable,  and  both  are  rendered  hard  by 
solutions  of  the  bi-chloride  of  mercury.  According  to 
the  analysis  of  M.  Vauquelin,  the  nervous  substance  is 
composed  of  the  following  ingredients: — a  white  fat,  4  53; 
a  reddish  brown  liquid  fat,  called  cerebrin,*  by  M.  Chev- 
reul,  0.7;  water,  80;  albumen,  7.0;  osmazome,  1.12;  phos- 
phorus, 1.5;  phosphate  of  potash,  muriate  of  soda,  phos- 
phate of  lime,  and  phosphate  of  magnesia,  5.15.  The 
quantity  of  albumen  is  in  an  inverse  ratio  to  that  of  the 
fatty  matter,  which  is  most  abundant  in  the  spinal  marrow, 
less  in  the  brain,  and  quite  small  in  the  nerves:  the  phos- 
phorus appears  to  exist  only  in  the  medullary  substance. 
The  analysis  of  Vauquelin  has  no  reference  to  the  grayish 
substance  of  the  ganglia  of  the  great  sympathetic. 

Order  of  development  and  differences  according  to 
age. — We  have  no  positive  knowledge  with  regard  to  the 
time  in  which  the  nervous  system  begins  to  be  perceptible, 
nor  of  the  state  in  which  it  is  at  its  origin.  It  appears, 
however,  to  be  one  of  the  first  of  the  systems  that  are  de- 
veloped. Its  different  parts  are  not  formed  simultaneous- 
ly, but  in  a  gradual  and  successive  manner;!  and  though 
authors  are  not  agreed  upon  the  order  of  this  succession, 
it  would  appear  sufficiently  evident  that  the  nerves  and 
their  ganglia  appear  first;  then  the  medulla  spinalis,  and 
finally,  the  different  parts  of  the  encephalon.  This  general 
order,  and  that  which  we  shall  point  out  hereafter,  when 
speaking  of  each  part  of  the  central  masses  in  particular, 
correspond  to  that  in  which  the  nervous  system  is  pro- 

*  According1  to  M.  Chevreul,  this  substance  also  exists  in  the  blood. 

t  This  progress  of  the  development  of  the  nervous  organs  is  not,  as 
the  ancients  thought,  the  result  of  a  vegetative  elongation  of  the  pri- 
mary parts  of  this  system. 


OF  THE  NERVOUS  SYSTEM.  151 

gressively  complicated  in  the  animal  scale,  in  ascending 
from  the  inferior  to  the  higher  classes.  This  fact  consti- 
tutes the  principal  anatomical  proof  of  the  plurality  of  the 
nervous  system.  Mr.  Gall  is  of  opinion  that  the  grayish 
substance  is  formed  previously  to  the  medullary;  but  ac- 
cording to  M.  Serres,  this  is  true  only  with  regard  to  the 
encephalon.  According  to  the  researches  of  Tiedemann, 
and  other  anatomists,  the  medullary  substance  appears  al- 
ways before  the  cortical;  and  this  opinion  appears  to  have 
the  most  probabilities  in  its  favour.*  Be  this  as  it  may, 
it  is  certain  that  the  nervous  substance  passes  through  all 
the  intermediate  gradations  between  fluids  and  solids,  being 
soft  in  infancy,  and  acquiring  consistency  by  degrees.  The 
growth  of  the  nervous  organs  is  effected  by  interstitial  nu- 
trition, and  by  the  deposition  of  layers  upon  their  surfaces, 
which  are,  apparently,  secreted  by  the  cellulo-vascular  mem- 
brane by  which  they  are  covered.  This  growth,  which  is 
extremely  rapid  during  foetal  life,  becomes  gradually  slow- 
er after  birth,  until  it  is  finally  converted  into  a  simple 
nutritive  process,  which  itself  diminishes,  so  that  at  length 
in  old  age  the  organs  of  which  we  are  treating,  have  sensi- 
bly lost  a  share  of  the  volume  which  they  had  acquired  in 
adult  age. 

Vital  properties  and  functions. — The  nervous  system 
is  essentially  sensible,  but  in  such  degrees  and  conditions 
as  vary  according  to  the  different  parts  of  which  it  is  com- 
posed. It  is  to  its  presence  in  the  other  organic  systems 
that  are  owing  the  phenomena  of  the  sensibility  which  they 
enjoy.  This  sensibility  of  the  organic  systems  is  nothing 
but  a  modification  of  a  property  belonging  exclusively  to 
the  nervous  system — a  property,  which  physicians  have 
designated  by  the  names  of  vital  energy,  nervous  power, 

*  The  circumstance  which  has  led  physiologists  into  error  as  regards 
this  subject  is,  that  in  the  foetus,  the  medullary  substance  is  slightly  co- 
loured, which  is  owing  to  its  being  more  penetrated  by  the  fluids  dur- 
ing pregnancy  than  at  any  other  period . 


152  OF  THE  NERVOUS  SYSTEM. 

and  by  virtue  of  which,  it  animates  the  whole  animal 
economy,  and  performs  the  most  important  functions. 

Physiologists  have  at  all  times  endeavoured  to  ascertain 
the  nature  of  this  property :  how  far  they  have  succeeded 
will  appear  from  the  statement  of  the  principal  hypotheses, 
after  we  shall  have  described,  in  a  general  manner,  the  ac- 
tions which  depend  upon  it. 

The  nervous  system  is  the  apparatus  of  innervation,  a 
multiple  function,  at  least  as  to  its  results,  by  which  it  ani- 
mates all  our  organs,  presides  over  all  their  vital  actions, 
both  voluntary  and  involuntary,  transmits  and  receives  the 
sensorial  and  affective  impressions,  and  is  the  agent  of  the 
operations  of  intelligence. 

Every  part  of  the  nervous  system  has  its  determinate 
function.  In  the  inferior  animals,  the  small  apparatus 
which  compose  this  system,  are  independent  of  each  other, 
and  their  actions  are  less  rigidly  specified;  but  in  ascend- 
ing the  scale  to  the  higher  classes,  we  find  the  functions  are 
multiplied  in  proportion  as  the  nervous  system  becomes 
more  complicated;  at  the  same  time  that  these  functions, 
though  always  distinct,  become  less  and  less  independent, 
and  are  placed,  moreover,  under  the  influence  of  a  centre 
of  action,  whose  integrity  is  necessary  to  their  perform- 
ance and  regularity.  This  physiological  centre  of  action, 
to  which  we  have  just  alluded,  is  the  encephalon,  and  par- 
ticularly the  medulla  oblongata,  upon  which  depend  all  the 
other  parts  of  the  nervous  system,  as  well  as  the  functions 
which  they  perform,  in  proportion  as  they  have  less  for 
their  object  the  nutrition  of  the  individual. 

The  grayish  substance  of  the  nervous  tissue,  as  has  been 
demonstrated  by  Mr.  Tiedemann,  increases  the  activity  of 
the  medullary,  by  concentrating  a  greater  quantity  of 
blood  towards  the  parts  where  this  activity  is  more  essen- 
tially necessary:  thus  the  substance  of  which  we  are  speak- 
ing is  very  abundant  in  the  medulla  spinalis,  at  the  origin 


OF  THE  NERVOUS  SYSTEM.  153 

of  the  nerves,   and  more  so  in  proportion   as   these  are 
larger. 

Physiologists  have  not  been  contented  with  merely  re- 
ferring the  faculty  of  the  senses  and  innervation  to  a  peculiar 
property  of  the  nervous  system,  but  they  have  also  endea- 
voured to  ascertain  the  nature  of  these  functions.  The  hy- 
potheses that  have  been  advanced  upon  this  subject,  may 
be  reduced  to  two  principal  ones,  both  very  old.  Accord- 
ing to  the  first,  which  has  had  the  smallest  number  of  sup- 
porters, the  nerves  perform  their  functions  by  the  centri- 
petal and  centrifugal  transmission  of  vibrations,  excited  in 
the  one  case  by  external  agents,  and  in  the  other  by  the 
brain,  the  point  of  egress  of  innervation  and  volition.  In- 
dependently of  the  fact  that  this  hypothesis  is  founded 
upon  no  direct  experiment,  it  would  be  entirely  inadmis- 
sible from  the  circumstance,  that  the  nerves  are  too  soft  to 
perform  the  office  of  vibrating  cords.  The  second  suppo- 
sition has  had  by  far  the  greatest  number  of  partizans,  and 
ranks  amongst  its  number,  the  most  celebrated  physicians 
of  both  ancient  and  modern  times,  and  amongst  others,  the 
immortal  Galen,  Baglivi,  Boerhaave,  Haller,  &c.  This 
hypothesis  consists  in  the  admission  of  a  subtile  fluid  which 
is  secreted  by  the  brain,  and  is  designated  by  the  names  of 
nervous  fluid,  animal  spirit,  and  pervades  the  nerves  with 
the  greatest  rapidity,  from  their  cerebral  to  their  periphe- 
ral extremity,  and  vice  versa-,  transmitting  to  the  centre  of 
the  nervous  system  the  impressions  which  are  received 
by  the  sentient  extremities  of  the  nerves,  and  carrying  to 
the  organs,  the  volitions  and  the  nervous  influx  emanating 
from  the  brain.  Some  have  even  gone  so  far  as  to  imagine 
there  are  two  fluids,  destined,  each  to  one  of  these  motions, 
and  so  subtile,  that  they  might  traverse  the  same  nervous 
cords,  in  an  inverse  direction  at  the  same  instant:  while 
other  physiologists,  to  explain  the  differences  of  the  sensa- 
tions in  the  brain,  and  of  the  volitions,  &.c,  which  are  de- 
rived from  it,  have  combined  the  two  hypotheses,  and  have 
21 


154  OP  THE  NERVOUS  SYSTEM. 

attributed  the  first  to  vibrations,  and  the  second  to  animal 
spirits.  Finally,  this  association  of  hypotheses,  has  been 
inverted,  and  the  hypothesis  of  animal  spirits  has  been 
modified  in  various  ways.  No  sooner  was  this  admitted, 
than  physiologists,  anxious  to  ascertain  its  nature,  advanc- 
ed the  most  absurd  and  ill  founded  propositions;  so  that 
the  only  one,  which  is  at  all  plausible  and  worthy  of  our 
attention,  is  that  which  compares  the  nervous  agent  to  the 
electric  fluid. 

In  the  present  day,  physiologists  are  contented  with  ob- 
serving the  laws  of  innervation,  and,  if  they  go  beyond 
this,  it  is  with  the  view  of  drawing  conclusions  from  the 
remarkable  analogy  which  exists  between  certain  effects  of 
electricity  upon  the  animal  organization,  either  dead  or  liv- 
ing, and  the  vital  phenomena,  which  allow  us  to  presume 
the  existence  of  an  imponderable  agent,  which  presides 
over,  and  regulates  the  functions  of  the  nervous  system. 


section  2. 
Of  the  Nervous  Centres. 

ARTICLE    1. 

Of  the  Cerehro-Spinal  Centre 

Definition. — By  the  term  cerebro-spinal,  we  under- 
stand, with  most  modern  authors,  the  mass  of  nervous  sub- 
stance which  is  contained  within  the  cavities  of  the  cra- 
nium and  the  vertebral  column.* 

*  We  must  recollect  that  this  mass  comprehends,  according'  to  Messrs. 
Gall  and  de  Blainville,  a  series  of  ganglia,  so  many  centres  of  small  sys- 
tems or  nervous  apparatus,  and  having,  according  to  the  latter  physiolo- 
gist, a  common  centre — the  spinal  marrow:  these  divisions,  however 
various  they  may  be,  are  not  in  contradiction  with  the  ancient  denomina- 
tion of  cerebrospinal  centre, — a  collective  denomination  which  is  applied 
to  every  division  of  this  continuous  mass. 


OF  THE  NERVOUS  SYSTEM.  15.5 

.  Division. — The  cerebro-spinal  centre  is  composed  (a) 
of  the  medulla  spinalis;  and  (b)  of  the  encephalon,  which 
comprehends  the  medulla  oblongata,  the  cerebrum  and 
cerebellum. 

Situation. — (a)  The  medulla  spinalis  is  situated  within 
the  vertebral  canal  which  is  formed  by  the  vertebrae  of  the 
neck,  the  back,  the  loins,  and  the  sacrum;  but  in  the  hu- 
man subject,  it  extends  only  from  the  superior  part  of  this 
canal  to  a  level  with  the  second  lumbar  vertebra. 

(b)  The  encephalon  is  situated  at  the  superior  part  of  the 
medulla  spinalis,  with  which  it  is  continuous,  and  fills  com- 
pletely the  cavity  of  the  cranium. 

Form  and  arrangement. — (a)  The  spinal  marrow  is  a 
large  nervous  fasciculus,  irregularly  cylindroid,  divided  into 
two  lateral  symmetrical  halves,  by  two  fissures  which  ex- 
tend throughout  the  whole  length  of  its  anterior  and  pos-ii 
terior  surfaces.  Each  lateral  half  comprehends  two  fasci- 
culi, an  anterior  and  a  posterior,  whose  line  of  demarcation 
is  marked  out  by  the  insertion  of  the  ligamentum  denticu- 
latum.  The  spinal  marrow  is  more  voluminous  superiorly 
than  inferiorly,  but  its  decrease  is  by  no- means  uniform: 
it  enlarges  where  it  gives  off  the  nerves,  and  this  in  propor- 
tion to  the  size  of  the  nerves  which  are  separated  sym- 
metrically from  its  lateral  parts,  to  the  amount  of  thirty 
pairs.  Superiorly,  the  spinal  marrow  enlarges  considera- 
bly in  entering  the  cranium,  where  it  begins  the  encephalon 
under  the  name  of  the  medulla  oblongata.  Here  it  presents 
three  pairs  of  lateral  and  symmetrical  fasciculi:  the  anterior, 
which  is  disposed  on  the  sides  of  the  mesian  fissure,  con- 
stitutes the  pyramidal  fasciculi,  which,  after  having  inter- 
changed fibres,  form  the  peduncles  and  hemispheres  of  the 
cerebrum;*the  second  pair  comprehends  the  middle  fasciculi, 

*  We  ought  not  to  understand  by  the  word  "  to  form"  a  real  vegeta- 
tive growth;  it  is  merely  expressive  of  the  order  of  development  and  of 
the  connexion  of  the  different  parts  of  the  encephalon. 


156  Or  THE  NERVOUS  SYSTEM. 

which  are  situated  on  the  outside  of  the  preceding,  and 
which,  being  reinforced  by  the  corpora  olivaria,  terminate 
in  the  tubercula  quadrigemina;  the  third  pair  or  the  pos- 
terior fasciculi,  are  strengthened  by  the  corpora  restiformia, 
and  form  the  cerebellum  and  tuber  annulare,  which  em- 
braces the  base  of  the  medulla  oblongata.  All  these  fasci- 
culi give  rise  to  smaller  ones  which  communicate  with,  and 
establish  relations  between,  every  part  of  the  encephalon. 
— The  encephalon,  regarded  as  a  whole,  constitutes  a  ta- 
bulated mass,  irregularly  hemispherical,  composed  of  sym- 
metrical portions,  presenting  depressions  and  correspond- 
ing eminences,  and,  in  short,  a  very  complicated  struc- 
ture, for  a  minute  description  of  which,  we  must  refer  to 
descriptive  anatomy.  The  medulla  oblongata  is  the  only 
part  of  the  encephalon  that  gives  origin  to  nerves. — The 
^encephalo-rachidian  mass  is  surrounded  and  protected  by 
three  kinds  of  membranes;  the  external  belongs  to  the 
fibrous  system  and  is  termed  the  dura  mater;  the  middle  is 
a  kind  of  serous  membrane,  and  is  called  the  tunica  arach- 
noides;  the  internal  is  the  pia  mater,  a  very  delicate  cellulo- 
vascular  net-work,  applied  immediately  upon  the  nervous 
masses,  lining  all  the  sinuosities  upon  the  surface  of  the 
encephalon,  and  dipping  into  the  anterior  and  posterior 
furrows  of  the  spinal  marrow.  We  must  recollect  that 
Mr.  Gall  considers  the  medulla  spinalis  and  the  encephalon 
as  a  series  of  ganglia  connected  together  by  intermediate 
fasciculi,  and  that  M.  de  Blainville  professes  a  nearly  simi- 
lar opinion,  with  the  exception  that  he  regards  the  spinal 
marrow  as  a  single  ganglion — the  centre  of  all  the  others; 
and  reduces  the  encephalic  ganglia  to  seven  pairs,  as  we 
have  already  seen  in  the  preceding,  section. 

Texture. — It  is  only  in  the  cerebro-spinal  mass  that  we 
observe  the  two  kinds  of  nervous  substance,  the  white  and 
the  grajash.  Their  relations  of  situation  and  quantity 
vary  in  the  different  parts  of  this  mass;  thus,  in  the  spinal 
marrow,  the  grayish  substance  is  interiorly  and  surround- 


OF   THE  NERVOUS  SYSTEM.  157 

ed  by  the  white,  which  is  disposed  around  it  in  the  form 
of  a  layer: — the  grayish  substance  is  most  abundant  at  the 
points  where  the  large  nerves  are  given  off.  In  the  ence- 
phalon,  on  the  contrary,  the  grayish  substance  forms  the 
exterior  and  cortical  layer  of  the  hemispheres  of  the  cere- 
brum and  cerebellum,  while  the  white,  which  is  surround- 
ed by  it,  composes  the  whole  interior  of  these  parts.  Be- 
sides, in  the  medulla  oblongata,  the  peduncles  of  the  cere- 
brum and  cerebellum,  &c,  we  meet  with  masses  of  the 
grayish  substance,  which  are  enveloped  by  white  fibres, 
(origin  of  the  encephalic  nerves),  and  alternate  layers  of 
both  substances,  &c.  In  this  variety  of  arrangement,  there 
is  but  one  general  law — that  of  the  continuity  of  the  white 
substance  throughout  the  whole  encephalo-rachidian  mass, 
and  the  insulation  of  the  different  parts  of  the  grayish. 
The  fibres  of  the  medullary  substance,  the  only  ones  that 
are  at  all  conspicuous,  are  much  less  apparent  in  the  cere- 
brospinal mass,  than  in  the  nerves;  they  are  parallel  in  the 
two  fasciculi  of  the  spinal  marrow,  which  are  connected 
together  by  transverse  fibres,  and  not,  as  some  anatomists 
have  asserted,  by  a  decussation  of  their  filaments.  There 
is  nearly  the  same  arrangement  with  regard  to  those  of  the 
medulla  oblongata,  with  the  exception  that  they  are  more 
divergent,  and  that  those  of  the  two  anterior  or  pyramidal 
fasciculi  are  interlaced  upon  the  mesian  line.  The  fibres  of 
the  peduncles  of  the  cerebrum  and  the  cerebellum  proceed 
in  radii  to  form  the  hemispheres  of  these  organs,  and,  if 
we  may  credit  Mr.  Gall,  these  diverging  fibres,  after  hav- 
ing reached  the  grayish  substance  that  forms  the  cortical 
layer  of  the  hemispheres,  are  reflected  upon  the  mesian 
line,  under  the  name  of  the  converging  fibres,  to  form  the 
corpus  callosum  and  the  commissures.  This  manner  of 
observing  has  been  disputed  by  Mr.  Tiedemann,  who  re- 
gards the  cerebral  commissures  and  the  corpus  callosum  as 
being  derived  from  the  cerebral  peduncles.  The  cortical 
substance  of  the  cerebrum  and  the  cerebellum  is  so  abun- 


15S  OP  THE  NEltVOUS  SYSTEM. 

dantly  supplied  with  blood-vessels,  that,  when  well  inject- 
ed, it  appears  to  be  almost  entirely  composed  of  them. 
To  judge  of  the  vascularity  of  both  the  white  and  the  cor- 
tical substances,  it  will  be  sufficient  merely  to  tear  them; 
we  shall  then  observe  that  they  are  covered  with  small 
reddish  points,  which  are  more  or  less  conspicuous,  and  are 
more  numerous  in  the  grayish  than  in  the  medullary  sub- 
stance: these  points  are  the  extremities  of  the  small  blood 
vessels  that  have  been  ruptured. 

Characters,  physical  and  chemical  properties. — To 
what  we  have  already  said  upon  this  subject  in  the  gene- 
ral observations  of  the  nervous  system,  we  have  only  to 
add,  that  the  consistence  of  the  encephalo-rachidian  mass  is 
much  less  than  that  of  the  nerves. 

Order  of  development,  and  differences  according  to 
age. — The  spinal  marrow  is  developed  before  the  ence- 
phalon,  and  amongst  its  different  parts,  the  medulla  ob- 
longata is  the  first  that  comes  into  existence;  this,  which  is 
nothing  but  the  superior  portion  of  the  spinal  marrow,  has 
added  to  its  fasciculi  in  a  gradual  and  successive  manner, 
the  cerebellum,  the  tubercula  quadrigemina,  and  the  cere- 
brum. 

The  cerebellum  and  the  cerebrum  are  much  larger,  com- 
pared with  the  spinal  marrow,  in  proportion  as  the  subject 
is  farther  advanced  in  age;  while  the  tubercles  are  much 
larger  compared  with  the  brain,  as  the  foetus  is  younger, 
and  are  bigeminous  before  they  are  converted  into  the 
quadrigemena.  The  hemispheres  of  the  cerebellum  are 
at  first  equal  to  the  middle  lobe  (vermiform  process),  but 
as  they  increase,  they  greatly  exceed  it  in  size.  The  cere- 
bral hemispheres  form  by  far  the  larger  portion  of  the  en- 
cephalon,  and  project  farther  backwards  in  proportion  as 
the  nervous  system  is  more  perfectly  developed.  All  that 
we  have  just  observed  with  regard  to  the  human  foetus  is 
equally  applicable  to  the  different  classes  of  vertebral  ani- 
mals. 


OF  THE  NERVOUS  SYSTEM.  159 

The  encephalo-rachidian  mass  is  at  first  nothing  but  a 
semi-fluid  substance,  which  subsequently  and  by  degrees, 
assumes  the  characters  of  the  white  nervous  substance, 
and  finally  unites  with  the  grayish  substance  which  is  se- 
creted by  the  pia  mater.  In  old  age  the  spinal  marrow  and 
the  encephalon  become  more  dense,  and  there  is  a  very 
sensible  diminution  of  volume. 

Vital  properties  and  Junctions. — Although  the  ence- 
phalon and  the  spinal  marrow  enjoy  the  highest  degree  of 
nervous  energy,  there  are  not  wanting  some  who  have  en- 
deavoured to  deny  the  sensibility  of  the  brain.  This  error 
would  not  have  been  committed,  if  physiologists  had  been 
aware  of  the  fact  that,  though  there  are  some  organs  which 
can  not  be  rendered  painful  by  external  irritants,  they  may 
be  all  excited  by  internal  causes,  whether  physiological  or 
.pathological. 

We  have  already  seen,  that  modern  anatomists,  in  ad- 
mitting the  plurality  of  the  nervous  system,  recognize  an 
assemblage  of  distinct  masses  or  ganglia  in  the  cerebrospi- 
nal centre,  and  attribute  to  each  of  them  a  determinate 
function,  which  it  exercises  in  virtue  of  its  nervous  energy, 
and  which  is  placed  under  the  influence  of  a  common  cen- 
tre. By  thosfe  (Magendie)  who  do  not  consider  with  M. 
de  Blainville,  that  the  spinal  marrow  is  the  central  part  of 
the  nervous  system,  it  is  regarded  as  the  seat  of  general 
sensibility.  The  posterior  part  of  the  spinal  marrow,  some 
parts  of  the  medulla  oblongata,  and  according  to  some,  the 
cerebellum,  appear  destined  especially  to  the  external  sen- 
sations. The  anterior  portion  of  the  spinal  marrow,  that 
of  the  medulla  oblongata  which  gives  rise  to  the  motor 
nerves  of  the  face,  and,  according  to  Magendie,  the  cere- 
bellum and  some  parts  of  the  base  of  the  cerebrum,  preside 
over  the  voluntary  motions.  Finally,  the  cerebrum  is  the 
seat  of  the  internal  or  affective  sensations  and  of  the  intel- 
lectual faculties.  The  spinal  marrow  is  really  nothing  but 
an  organ  of  transmission;  perceptions  and  determinations 


160  OF  THE  NERVOUS  SYSTEM. 

belong  to  the  cncephalon.  The  portion  of  the  medulla  ob- 
longata from  which  originate  the  peduncles  of  the  cerebrum 
and  the  cerebellum,  appears  to  be  the  physiological  centre 
of  the  encephalo-rachidian  mass,  and  consequently,  of  the 
Avhole  system.  Nevertheless,  physiologists  have  come  to 
very  different  conclusions  with  regard  to  the  parts  of  this 
mass  which  correspond  to  the  different  functions  of  inner- 
vation. 

Pathological  Jinatomy. 

There  are  observations  which  would  induce  Us  to  believe 
that  the  brain  is  susceptible  of  undergoing  a  diminution  of 
volume  before  old  age,  but  it  does  not  appear  that  it  is 
ever  subject  to  hypertrophia.  The  conformation  of  the 
cerebro-spinal  masses,  is  sometimes  altered  by  the  pres- 
sure of  tumours  situated  in  their  neighbourhood.  The 
spinal  marrow  is  often  compressed  by  curvatures  of  the 
spine,  and  altered  in  its  form,  though  most  frequently 
without  creating  any  disturbance  in  its  functions.  The 
solutions  of  continuity  of  the  encephalon  and  the  spinal 
marrow,  when  they  do  not  terminate  fatally,  heal,  like 
those  of  the  other  organs,  either  by  immediate  re-union,  or 
by  the  formation  of  a  brain-like  substance,  which  is  depo- 
sited upon  the  points  that  have  been  left  open  from  the  loss 
of  substance,  or  by  the  simple  separation  of  the  lips  of  the 
wound.  In  cases  of  apoplexy  and  in  certain  cerebral  dis- 
turbances, where  there  is  an  effusion  of  blood  or  serum 
into  the  nervous  tissue,  if  the  subject  be  young,  the  fluid  is 
soon  surrounded  by  a  cyst,  and  is  gradually  absorbed;*  and 
its  parietes  approximate  and  form  adhesions  so  as  to  com- 
pletely obliterate  its  cavity. 

The  organs  of  which  we  are  treating  are  very  frequent- 
ly subject  to  sanguineous  congestions,  which  can  be  readi- 

*  In  tliis  case,  the  blood  is  decomposed  into  its  two  elements,  the  clot 
and  the  scrum,  and  becomes  really  a  foreign  bod}-. 


OF  THE  NERVOUS  SYSTEM-  161 

ly  explained  by  the  great  quantity  of  blood  which  they 
receive,  and  by  the  facility  with  which  it  exalts  their  ac- 
tivity. Inflammation  of  these  organs  is  by  no  means  a 
rare  disease,  and  is  generally  accompanied  by  that  of  the 
meninges.  Inflammation  of  the  encephalon  and  medulla 
spinalis  is  characterized  by  the  redness  and  softening  of 
their  substance,  and  sometimes,  by  suppuration,  ulceration, 
and  even  gangrene.  The  sub-inflammatory  state  of  the 
nervous  central  masses  may  also  give  rise  to  the  secretion 
of  purulent  matter,  which  is  sometimes  collected  in  a  sin- 
gle abscess,  in  the  substance  of  the  organ,  and  excites  the 
formation  of  a  cyst  in  which  it  remains  for  a  variable  time; 
at  other  times,  the  secretion  is  nothing  but  serum,  which 
is  collected  either  in  the  ventricles  of  the  brain,  or  in  the 
nervous  substance  itself,  or  between  the  organ  and  its  en- 
velopes: when  this  is  the  case,  it  constitutes  what  physicians 
call  acute  hydrocephalus,  a  disease  which  diners  from  chro- 
nic hydrocephalus,  inasmuch  as  the  latter,  which  is  most 
generally  congenital,  is  not  accompanied  by  any  inflamma- 
tory process.  When  this  affection  attacks  the  spinal  mar- 
row and  its  coverings,  it  is  termed  hydro-rachitis,  of  which 
the  disease  termed  spina-bifida  is  a  remarkable  variety.  In 
consequence  of  the  chronic  phlegmasia,  the  cerebro-spinal 
centre  is  also  sometimes  affected  with  tuberculous,  schir- 
rous  and  carcinomatous  degenerations,  fungous  growths, 
and  fibrous,  fibro-cartilaginous,  and  osseous  transforma- 
tions. Hydatids  are  also  found  in  some  instances  in  the 
ventricles  of  the  brain,  and  even  in  the  substance  of  the 
encephalon  and  the  spinal  marrow.  These  organs  are  often 
subject  to  considerable  softening,  attended  with  a  very  va- 
riable change  of  colour;  in  many  cases  this  alteration  is 
evidently  the  result  of  chronic  inflammation.  Induration 
of  the  encephalo-rachidian  mass  is  another  disease  which 
exists  either  by  itself,  or  in  union  with  the  preceding.  The 
indurated  substance,   sometimes  perfectly  homogeneous, 

and,  in  appearance,  inorganic,  resembles  coagulated  albu- 
22 


162  OB'  THE  NERVOUS  SYSTEM. 

men;  at  others,  however,  it  is  more  evidently  fibrous.  This 
alteration  appears  to  be  more  peculiar  to  the  white  sub- 
stance. The  brains  of  idiots,  epileptics,  &c.  are  frequently- 
indurated  and  softened  to  a  greater  or  less  extent. 

The  encephalon  and  spinal  marrow  are  by  no  means  ex- 
empt from  mal-conformations:  the  entire  absence  of  these 
organs,  especially  of  the  encephalon  or  some  of  its  parts,  is 
not  an  unfrequent  occurrence.  From  the  existence  of  the 
rest  of  the  nervous  system,  under  these  circumstances,  it  is 
evident,  that  every  part  of  it  is  independent  as  regards  its 
development  and  origin.  In  the  early  age  of  the  foetus, 
the  spinal  marrow  presents  a  longitudinal  groove  on  its 
posterior  surface,  and  subsequently  a  central  canal*,  some- 
times we  observe  the  one  or  the  other  of  these  arrange- 
ments at  birth;  at  others,  this  organ  is  entirely  wanting, 
and  in  its  stead,  the  pia  mater  forms  a  canal  which  is  filled 
with  a  fluid,  and  gives  insertion,  as  it  naturally  does,  to  the 
roots  of  the  spinal  nerves. 

Amongst  the  defects  of  symmetry  which  are  sometimes, 
though  rarely  observed,  between  the  different  parts  of  the 
nervous  central  masses,  we  may  notice  the  disproportions 
which  occur  between  the  lobes  of  the  cerebrum. 


article  2. 

Of  the  Nervous  Ganglia. 

Definition. — The  nervous  ganglia  are  small  masses,  ir- 
regularly rounded,  and  situated  on  the  course  of  the 
nerves.* 

*  We  have  seen  that  Gall  and  De  Blainville  have  also  applied  the 
term  ganglion  to  the  divisions  of  the  cerebo-spinal  masses;  this  generali- 
zation, a  natural  consequence  of  then-  manner  of  regarding  the  nervous 
system,  gives  this  expression  an  exclusively  physiological  sense:  but  it 
should  not  be  used  when  we  consider  the  ganglia  in  a  less  exclusive 
point  of  view — under  that  of  their  structure. 


OF  THE  NEKVOUS  SYSTEM.  163 

Division. — The  ganglia  are  divided  into  two  classes; 
the  first  comprehends  those  which  belong  to  the  cerebro- 
spinal nerves,  and  the  second  those  which  occur  in  the 
course  of  the  trisplanchnic  nerve:  the  latter  may  again  be 
subdivided  into  those  which  form  a  double  series  upon 
the  sides  of  the  vertebral  column,  and  into  those  which  are 
more  immediately  upon  the  mesian  line. 

Situation. — The  nervous  ganglia  are  found  exclusively 
in  the  head,  the  neck,  and  in  the  cavities  of  the  thorax 
and  abdomen;  there  being  none  in  the  extremities.  The 
ganglia  of  the  first  class  occur  near  the  central  extremity, 
or  origin  of  some  of  the  encephalic,  and  at  the  posterior 
roots  of  all  the  spinal  nerves.  Amongst  the  ganglia  of  the 
second  class  or  of  the  trisplanchnic  nerve,  some  are  lateral, 
and  placed  in  a  double  series  upon  the  sides  of  the  anteri- 
or part  of  the  vertebral  column,  and  are  designated  by  the 
names  of  the  cervical,  the  thoracic,  the  lumbar  and  the  sacral 
ganglia;  in  this  enumeration  ought  to  be  included  the  small 
coccygean  ganglion,  which,  though  it  is  single  and  situated 
upon  the  mesian  line,  belongs  to  this  series.  The  other 
ganglia  of  the  second  class  are  more  immediately  upon  the 
mesian  line,  and  are  termed  the  cardiac  and  semi-lunar. 

Form  and  volume. — All  the  spinal  ganglia  are  of  an 
oval  form;  amongst  the  others,  some  are  oblong,  others  ir- 
regularly globular,  and,  in  a  word,  of  a  very  different  form. 
Their  volume  varies  from  that  of  a  lentil  to  that  of  an  al- 
mond. 

Structure. — On  dividing  of  the  ganglia,  their  tissue 
appears  at  first  sight  to  be  homogeneous;  but  after  they  have 
been  subjected  to  maceration  for  some  time,  we  find  that 
there  are  two  substances,  that  contribute  to  their  composi- 
tion: the  one  is  white  or  medullary,  and  is  disposed  in  fila- 
ments in  the  same  manner  as  in  the  nerves;  the  other  is  of 
a  grayish  red,  somewhat  pulpy,  different  from  the  grayish 
substance  of  the  encephalo-rachidian  mass,  deposited  in 
cells,  and  firmly  adherent  to  the  medullary  filaments,  and 


164  OF  THE  NERVOUS  SYSTEM. 

more  consistent  in  the  ganglia  of  the  trisplanchnic  than  in 
those  of  the  medulla  spinalis. 

The  medullary  filaments  are  evidently  the  continuation 
of  those  which  constitute  the  nerves  upon  whose  course 
the  ganglia  occur.  In  entering  the  ganglia,  the  cords  are 
deprived  of  their  neurilema.  and  are  divided  into  filaments, 
which,  after  having  plunged  into  the  grayish  substance 
with  which  they  are  intimately  connected,  especially  in 
the  ganglia  of  the  trisplanchnic,  are  separated  from  each 
other  to  re-unite  and  anastomose  in  such  a  manner  as  to 
present  a  very  complicated  arrangement  in  the  ganglia  of 
the  second  class,  and  sufficiently  simple  in  those  of  the 
first.  The  medullary  filaments,  being  again  united  with 
the  cord,  issue  from  the  cerebro-spinal  ganglia  by  the  ex- 
tremity opposite  to  that  by  which  they  entered,  while, 
in  the  ganglia  of  the  trisplanchnic,  the  points  of  entrance 
and  of  egress  of  these  filaments  are  in  very  different  rela- 
tions of  situation.  All  the  nervous  ganglia  are  enveloped 
by  a  more  or  less  dense  membrane  which,  in  the  spinal,  has 
the  solidity  of  fibrous  tissue,  while  in  the  other  ganglia  it 
is  merely  a  membraniform  layer  of  cellular  tissue.  The 
blood  vessels  of  the  ganglia  are  exceedingly  numerous,  and 
most  of  them  send  branches  to  their  envelopes  before  they 
enter  the  ganglia  themselves.* 

Characters,  physical  and  chemical  properties. — The 
ganglia  are  of  a  grayish  red  colour,  which  is  most  conspi- 
cuous in  those  of  the  trisplanchnic,  which  are  also  harder 
than  the  others.  When  exposed  to  the  action  of  the  acids 
and  of  boiling  water,  they  are  at  first  hardened  and  final- 

*  In  comparing  these  details  upon  the  structure  of  the  ganglia  with 
what  we  shall  hereafter  say  with  regard  to  the  nervous  plexus,  we  shall 
see  whether  the  relations  which  exist  between  them  will  justify  the 
opinion  of  Scarpa,  and  other  authors  who  regard  the  terms  ganglia  and 
plexus  as  synonymous.  The  texture  of  the  first  is  evidently  more  com- 
plicated than  that  of  the  second,  and  their  uses,  moreover,  do  not  appear 
to  authorize  this  approximation. 


OF  THE  NERVOUS  SYSTEM.  165 

ly  softened;  they  are  slowly  dissolved  by  the  alkalies.  They 
resist  for  a  long  time  the  putrefactive  process;  and,  according 
to  Lobstein,  are  converted  into  a  kind  of  adipose  substance 
after  long  continued  maceration.— The  reddish  substance  of 
the  ganglia  does  not  consist  of  fat,  as  has  been  asserted  by  some 
who  have  adopted  the  opinion  of  Scarpa  upon  this  subject. 
According  to  the  chemical  researches  of  Wutzer  and  Las- 
saigne  upon  the  composition  of  the  ganglia,  they  contain 
less  adipose  substance  than  the  nerves,  and  much  less  than 
the  brain,  but  on  the  contrary  more  albumen  and  gelatine. 

Development  and  differences  according  to  age.  The 
spinal  ganglia  come  into  existence  before  any  of  the  others, 
and  even  before  the  rest  of  the  nervous  system,  with  the 
exception  of  the  nerves  which  belong  to  them.  The  gan- 
glia of  the  trisplanchnic  are  not  perceptible  before  the  third 
month  of  uterine  life:  they  are  all  from  the  beginning 
of  nearly  the  same  consistence  which  they  present  during 
the  course  of  life.  In  old  age  and  decrepitude  they  become 
smaller,  harder,  and  of  a  fainter  colour. 

Vital  properties  and  functions. — All  the  ganglia,  both 
of  the  cerebro-spinal  and  of  the  trisplanchnic  order,  are  desti- 
titute  of  contractility,  and  the  nervous  energy  appears  to  be 
distributed  to  them  in  the  same  manner  as  to  the  other  por- 
tions of  the  nervous  system;  though  it  seems  to  be  more 
energetic  in  the  spinal  ganglia  than  in  those  of  the  second 
class,  at  least,  if  we  may  judge  from  the  severe  pain  which 
accompanies  their  mechanical  or  chemical  irritation;  while 
those  of  the  trisplanchnic  are  entirely  free  from  pain  when 
they  are  the  seat  of  irritation  brought  on  by  some  internal 
cause. 

The  history  of  the  functions  of  the  ganglia  is  still  involv- 
ed in  the  greatest  obscurity.  According  to  some,  such  as 
Meckel  and  Scarpa,  they  are  destined  to  collect  and  blend 
the  nerves  or  the  nervous  filaments;  others,  such  as  Vieus- 
sens,  Winslow,  Reil,  Bichat,  and  others,  regard  them  as  fo- 
cal centres  of  the  nervous  action,  presiding  over  those  func- 


166  OF  THE  ISERVOUS  SYSTEM. 

tions  of  innervation  which  are  independent  of  volition, 
that  is,  over  the  actions  of  vegetative  life.  This  opinion, 
which  does  not  concern  the  ganglia  of  the  trisplanchnic, 
is  that  which  is  most  generally  adopted  at  the  present 
day.  Many  suppose,  also,  that  the  ganglia  arrest,  to  a  cer- 
tain degree,  the  impression  which  they  receive  from  the 
nerves  which  traverse  them;  that  they  concentrate  for  dis- 
tribution, the  nervous  energy  emanating  from  the  medulla 
spinalis,  and  that  in  this  manner  the  trisplanchnic  sys- 
tem is  rendered  independent  of  the  cerebro-rachidian 
masses:  we  ought  not,  however,  as  the  authors  to  whom 
we  have  just  alluded,  exaggerate  this  independence,  which 
is  merely  relative.  As  yet  we  are  entirely  ignorant  of 
the  functions  of  the  encephalic  and  spinal  ganglia;  M.  de 
Blainville  considers  them  as  the  centres  of  the  nerves  to 
which  they  belong. 

Alterations. — This  part  of  the  history  of  the  ganglia  is 
still  involved  in  the  mists  of  obscurity.  Several  authors, 
and  amongst  others  Mr.  Lobstein,  have  observed  inflamma- 
tion of  these  organs  in  several  diseases,  such  as  tetanus, 
pertussis,  and  in  some  of  the  abdominal  neuroses.  Bichat 
once  found  the  semi-lunar  ganglion  more  dense,  and  in 
another  instance  more  voluminous  than  natural:  this  last 
anomaly  was  accompanied  by  the  presence  of  a  cartilaginous 
substance  in  the  centre  of  the  small  organ:  the  subject  that 
presented  it  had  died  in  consequence  of  a  periodical  ma- 
nia. Anatomists  have  also  observed  cases  of  hypertrophia 
and  atrophia  of  the  ganglia  of  the  trisplanchnic;  and,  indeed, 
it  would  appear  probable  that  most  of  the  abdominal  neu- 
croses  depend  upon  an  alteration  of  these  organs. 


OF  THE  NERVOUS  SYSTEM.  167 

SECTION.    3. 

Of  the  Nerves. 

ARTICLE  1. 

Of  the  Cerebro-Spinal  Nerves. 

Definition. — The  cerebro-spinal  nerves  are  the  white 
cords,  which  are  connected  by  their  central  extremities  to 
the  substance  of  the  encephalon  or  the  spinal  marrow,  and 
terminate,  after  successive  ramifications,  in  certain  organs 
which  are  more  or  less  near  the  periphery  of  the  body. 

Division. — We  may  divide  the  nerves,  according  to  the 
seat  of  their  central  extremity,  into  encephalic  and  rachi- 
dian;  according  to  the  manner  in  which  they  are  detached 
from  this  extremity,  into  nerves  with  a  double,  and  into 
those  with  a  single  root;  and,  finally,  according  to  their 
functions,  into  the  sensitive,  motor,  and  mixed.  Each  of 
these  last  divisions  is  again  subdivided  before  it  comes  un- 
der the  last  term  of  specification:  this  subdivision  can  not 
be  pointed  out  on  the  present  occasion  without  anticipating 
some  of  the  subjects  of  this  article. 

Situation. — The  central  extremity  of  the  nerves  of 
which  we  are  treating,  is  situated  within  the  cavities  of  the 
cranium  and  the  vertebral  column;  and  the  other  approaches 
the  periphery  of  the  body  in  proportion  as  the  nerves 
ramify. 

Conformation. — In  consequence  of  their  numerous  anas- 
tomoses, the  cerebro-spinal  nerves,  considered  as  a  whole, 
represent  the  form  of  a  grand  net- work,  which  is  much 
more  symmetrical  in  its  two  lateral  halves,  in  proportion 
as  it  approaches  the  nervous  centres.  Their  particular  in- 
dividual form  is  generally  cylindrical;  some  of  them,  how- 
ever, are  flattened  and  ribband-like.     Examined  with  a 


168  OP  THE  NERVOUS  SYSTEM. 

magnifying  glass,  their  surface  presents  small  spiral  folds, 
which  belong,  however,  merely  to  the  neurilema. 

Central  extremity ',  improperly  called  the  origin  of  the 
nerves. — All  the  encephalo-rachidian  nerves  communicate 
by  their  central  extremity  with  the  spinal  marrow,  or  the 
medulla  oblongata;  there  being  none  detached  either  from 
the  cerebellum  or  from  the  brain  properly  so  called-.  The 
nerves  are  always  implanted  in  the  grayish  substance  of 
the  spinal  marrow,  and  the  medulla  oblongata,  and  may  be 
traced  farther  than  the  point  where  they  are  separated. 
They  do  not  intercharge  filaments  at  their  origin,  as  has 
been  supposed  by  those  who  have  endeavoured  to  explain 
in  this  manner  the  symptoms  of  paralysis,  and  partial  con- 
vulsions in  the  lateral  half  of  the  body  opposite  to  that  in 
which  the  lesion  occurred.*  By  the  root  of  a  nerve  we 
understand  its  central  extremity,  and,  according  as  it  is 
single  or  bifurcated,  we  say  that  the  nerve  has  one  or  two 
roots.  All  the  encephalic  nerves  belong  to  the  first  class, 
with  the  exception  of  the  trigeminus,  which,  together  with 
all  the  spinal  and  the  sub-occipital  nerves,  is  comprehended 
in  the  second. — The  nerves  with  double  roots  are  attached 
by  the  one,  to  the  anterior  fasciculi,  and  by  the  other,  to  the 
posterior  fasciculi  of  the  spinal  marrow.  It  is  to  the  pos- 
terior roots  alone  that  the  spinal  ganglia  belong — the  ante- 
rior roots  being  simply  appended  to  them. 

Course. — In  receding  from  their  central  extremity,  the 
nerves  are  successively  divided  into  branches,  smaller 
branches  and  filaments,  by  the  simple  separation  of  the  fasci 
culi  and  the  cords,  by  the  union  of  which  their  trunk  is  com- 
posed. In  their  course,  the  nerves  form  connexions  either 
between  themselves,  or  with  the  neighbouring  nerves,  by 
simple  anastomoses,  or  by  a  kind  of  complicated  interlace- 
ment, termed  plexus.     The  anastomoses  take  place  by  the 

*  The  optic  are  the  only  nerves  which  decussate,  and  this  only  in  a 
partial  manner,  and  after  their  separation  from  the  encephalon. — In  fishes 
this  decussation  is  complete. 


OP  THE  NERVOUS  SYSTEM.  169 

junction  of  two  nerves,  which  are  very  intimately  united 
by  the  continuity  of  substance,  and  are  finally  confounded 
with  each  other.  The  plexuses  are  anastomotic  unions  be- 
tween several  nerves  which  converge  towards  one  com- 
mon point:  these  anastomotic  junctions  are  formed  in  such 
a  manner,  that  the  nerves  which  issue  from  the  plexus  con- 
sist of  filaments  which  are  derived  from  all  the  nerves  that 
enter  into  the  formation  of  the  plexus.  The  cervical,  lum- 
bar, sacral,  and  sciatic  plexuses  are  the  principal  of  the 
cerebro-spinal  system.  The  nerves  generally  retain  the 
same  volume  from  their  origin  to  the  place  where  they  are 
divided j  and  the  aggregate  of  their  divisions  presents  a 
greater  volume  than  that  of  the  trunk  from  which  they  are 
derived. 

Peripheral  extremity ',  or  termination. — After  repeated 
and  numerous  ramifications,  the  cerebro-spinal  nerves  ter- 
minate in  the  integuments,  in  the  organs  of  the  special 
senses,  in  the  exterior  muscles,  in  the  arteries  of  the  parts 
which  are  subject  to  the  influence  of  volition,  &c.  When 
they  have  arrived  at  their  termination,  the  nervous  filaments 
are  deprived  of  their  neurilema,  and  become  sensibly  en- 
larged: and  this  is  all  that  we  know  positively  upon  this 
subject.  Amongst  the  anatomists  that  have  endeavoured  to 
penetrate  farther,  some  have  supposed,  but  have  never  de- 
monstrated, the  existence  of  a  kind  of  fusion  of  the  nerve  in 
the  substance  of  the  organ  in  which  it  terminates;  others 
have  said,  that  the  nervous  filaments,  after  they  have  ar- 
rived at  their  termination,  are  reflected  upon  themselves, 
and  return  to  the  branch  from  which  they  have  been  derived. 

Structure. — At  first  sight,  the  nerves  seem  to  be  compos- 
ed of  a  certain  number  of  cords  which  are  divisible  into  fila- 
ments of  great  tenuity:  these  are  composed,  1st,  of  a  white 
nervous  substance,  disposed  in  parallel  fibres;*  and  2d,  of  a 

*  According1  to  the  recent  observations  of  Prevost  and  Dumas,  the 
nerves  are  composed  of  a  very  greatnumber  of  parallel  filaments  which  are 
of  equal  size,  and  are  flat  and  continuous  throughout  the  whole  length  of 
23 


170  OF  THE  NERVOUS  SYSTEM. 

membranous  sheath  or  envelope  termed  neurilema.  All  the 
filaments  which  enter  into  the  composition  of  the  nervous 
cords,  have,  besides  their  proper  neurilema,  a  common  one; 
and  in  the  same  manner  all  the  cords  which  enter  into  the 
composition  of  the  nerves  have  a  general  neurilema. 

The  nervous  cords  are  placed  upon  each  other,  give  off 
filaments  of  communication,  and  present  a  plexiform  union : 
the  same  arrangement  is  found  between  the  filaments, 
which,  by  their  union,  constitute  the  cord;  so  that  neither 
the  one  nor  the  other  retain  the  same  situation  throughout 
the  whole  extent  of  the  nerve. 

Towards  the  central  extremity  of  the  nerves,  the  neu- 
rilema leaves  first  the  filaments,  then  the  cords,  and  where 
the  nerve  is  continuous  with  the  pia  mater,  the  gene- 
ral neurilema  alone  remains.  It  results  from  this  arrange- 
ment, that  when  a  nerve  is  torn  from  the  central  mass,  its 
interior  part  will  break  before  those  which  are  strengthen- 
ed by  the  general  neurilema,  and  leave  a  projection,  which 
is  believed  by  some  to  be  destined  for  the  insertion  of  the 
nerve.  We  have  already  seen  that  the  neurilema  leaves 
the  nerve  entirely  at  its  peripheral  extremity. 

The  nerves  are  surrounded  by  a  layer  of  cellular  tissue, 
which  penetrates  between  their  cords  and  filaments,  so  as 
to  unite  them  mutually  together.  The  neurilema  itself  is 
nothing  but  a  condensed  cellulo-vascular  tissue,  which  some 
anatomists  have  placed  in  the  fibrous  system.     No  lym- 

* 
the  nerve.  Each  filament  consists  of  four  elementary  fibres;  two  external, 
and  well  marked,  and  two  middle  and  less  distinct.  These  fibres  are  form- 
ed each  of  a  series  of  globules,  like  those  of  every  part  of  the  nervous 
system.  Bogros  asserts  that  he  has  demonstrated  by  minute  injections, 
which  do  honour  to  his  skill,  that  the  nervous  pulp  is  hollow  in  the  cen- 
tre of  the  nerves.  His  experiments  have  been  repeated  by  other  anato- 
mists, but  not  uniformly  with  the  same  results.  We  are  therefore  at 
present  unable  to  decide,  whether  the  canal  admitted  by  Bogros,  does 
really  exist  before  the  injections  which  render  it  obvious,  or  whether  it 
is  merely  the  result  of  these  injections. 


OF  THE  NERVOUS  SYSTEM.  171 

% 

phatics  can  be  traced  into  the  substance  of  the  nerves;  but 
their  blood  vessels  are  very  numerous  and  penetrate  the  * 
neurilema  as  far  as  the  nervous  filaments. 

Characters,  physical  and  chemical  properties. — The 
cerebro-spinal  nerves  possess  but  a  slight  degree  of  elasticity, 
are  of  a  faint  rose  colour,  and  owe  to  their  neurilema  the 
slight  degree  of  tenacity  which  they  enjoy.  The  dilute  acids, 
especially  the  nitric,  dissolve  the  neurilema,  and  expose  the 
nervous  pulp,  while  the  alkaline  solutions  destroy  it  and 
leave  the  neurilema  untouched;  it  is  this  knowledge  of  the 
modus  operandi  of  the  acids  and  alkalies  upon  the  nerves, 
that  has  furnished  Reil  with  the  means  of  analysing  and 
detecting  the  anatomical  elements  which  contribute  to  their 
structure.  The  medullary  substance  of  the  nerves  yields 
a  greater  quantity  of  albumen,  but  less  of  the  fatty  sub- 
stance, than  the  encephalo-rachidian  masses. 

Development. — The  cerebro-spinal  nerves,  are  the  first 
parts  of  the  nervous  system  of  the  embryo  that  are  brought 
into  existence.  In  the  foetus,  they  are  proportionably 
more  vascular  than  they  are  subsequently,  but  their  struc- 
ture is  indistinct,  and  their  neurilemic  part  appears  to  ex- 
ceed the  medullary,  which  is  nothing  but  a  mere  liquid. 
The  volume  of  the  nerves  is  much  greater  in  proportion  to 
that  of  the  encephalo-rachidian  centre,  as  they  are  exam- 
ined near  the  period  of  conception.  In  old  age,  they  are 
smaller,  more  dry  and  firm,  than  in  adult  life,  at  the 
same  time  that  their  vitality  is  less  energetic. 

Vital  properties  and  functions. — The  nervous  energy 
of  the  organs  of  which  we  are  treating,  is  rendered  evident 
by  the  violent  pains  and  the  muscular  contractions  which 
are  occasioned  by  their  artificial  or  morbid  irritation.  This 
power  is  inherent  in  the  nerves,  and  is  merely  called  into 
action  by  that  of  the  medulla  spinalis,  and  the  encephalon; 
for,  when  we  irritate  a  motor  nerve,  that  has  been  sepa- 
rated from  these  centres  by  the  knife  or  ligature,  the  mus- 
cles to  which  it  is  distributed  are  agitated  with  convulsive 


172  OP  THE  NERVOUS  SYSTEM. 

motions.  Anatomists  have  hitherto  heen  unable  to  trace 
the  least  sign  of  vital  contractility  in  the  cerebro-spinal 
nerves. 

The  nerves  are  the  organs  which  transmit  to  the  centre  of 
perception,  the  impressions  which  they  receive  in  the  or- 
gans to  which  they  are  distributed,  and  carry  to  every  part 
of  the  body  the  nervous  power  upon  which  depends  the 
muscular  contractility.  They  are  thus  conductors  of  sen- 
sibility and  of  motion  by  a  double  action,  from  the  centre 
to  the  circumference,  and  from  the  circumference  to  the 
centre,  during  which  they  manifest  neither  the  vibrations 
nor  the  oscillations  that  have  been  admitted  by  some  au- 
thors to  explain  the  mechanism  of  the  functions  of  trans- 
mission. The  rapidity  with  which  they  are  performed  has 
induced  many  to  believe,  that  there  is  an  imponderable 
fluid,  analogous  to  that  which  produces  the  phenomena  of 
electricity,  and  of  which  the  nerves  are  the  mere  conduc- 
tors. Several  physiological  experiments  give  support  to 
this  hypothesis.  Be  this  as  it  may,  however,  we  ought  to 
distinguish,  amongst  the  en cephalo-rachidian  nerves,  those 
which  are  exclusively  devoted  to  the  transmission  of  mo- 
tion, or  the  mptor  nerves;  those  which  belong  merely  to 
the  functions  of  the  external  sensations,  or  the  sensitive 
nerves;  and  those  which  are  at  once  conductors  of  sensi- 
bility and  of  motion,  or  the  ?nixed  nerves.  The  first  two 
classes  comprehend  all  the  nerves  of  the  head,  with  the 
exception  of  the  fifth  pair,  which,  together  with  all  the 
spinal  nerves  is  included  under  the  class  of  mixed  nerves. 
Magendie,  however,  has  satisfactorily  demonstrated,  that 
even  in  the  spinal  nerves,  the  two  orders  of  functions  have, 
to  a  certain  degree,  their  distinct  seat;  that  the  anterior 
root  is  destined  to  motion,  and  the  posterior  to  sensibility.* 

*  Mr.  Charles  Bell  has  lately  .performed  a  great  number  of  experiments 
with  the  view  of  specifying  the  functions  of  the  nerves,  and  has  obtained 
very  important  results  to  physiology.  He  divides  the  nerves  into  regu- 
lar and  irregular:  the  first,  which  are  common  to  all  the  vertebral  ani- 


OF  THE  NERVOUS  SYSTEM.  173 

Pathological  Anatomy. 

The  nerves  sometimes  increase  in  volume,  in  conse- 
quence of  serous,  gelatinous,  or  fatty  infiltrations  of  their 
tissue;  they  are  often  compressed,  flattened,  or  displaced, 
from  the  development  of  tumours  in  the  surrounding  parts, 
and  their  atrophy,  which  sometimes  depends  upon  the  same 
cause,  may  also  be  the  result  of  the  cessation  of  their  func- 
tions, (paralysis.)  When  a  nerve  has  been  divided,  the 
two  extremities,  if  they  have  been  separated  but  a  small 
distance,  are  re-united  by  a  nervous  cicatrix,  and  the  mo- 
tions of  the  nerve,  at  first  interrupted  between  the  solution 
of  continuity  and  the  peripheral  extremity,  are  perfectly 
re-established.  The  manner  in  which  this  re-union  is  ef- 
fected, may  be  comprised  under  the  following  observations. 
The  superior  extremity  of  the  divided  nerve,   in  conse- 

mals,  preside  over  the  general  sensibility  and  voluntary  motions,  and 
comprise  the  spinal  nerves,  (including  the  sub-occipital,)  the  trifacial, 
or  fifth  encephalic  pair,  and  all  the  nerves  with  a  double  root;  the 
second  are  the  nerves  with  a  single  root,  and  being  connected  with  the 
preceding,  in  proportion  as  the  organism  is  complicated,  are  distributed 
to  the  organs  which  are  amply  provided  with  the  former,  and  preside 
over  the  special  functions.  Mr.  Bell,  having  divided  the  branches  of 
the  facial  nerve  of  an  ass,  (the  portio-duro  of  the  seventh  pah'  of  "Willis) 
which  are  distributed  to  the  nostrils,  paralysed  the  muscles  of  the  parts, 
but  those  only  which  are  subservient  to  respiration,  and  the  expression 
of  the  face:  on  the  contrary,  when  he  divided  the  superior  maxillary 
branch  of  the  fifth  pair,  the  skin  of  the  face  was  deprived  of  sensibility, 
and  the  subjacent  muscles  lost  their  contractility,  with  the  exception  of 
those  which  perform  the  motions  of  respiration  and  expression,  whose 
nerves  were  left  undivided.  From  these  facts,  and  others  of  a  similar 
nature,  Mr.  Bell  concludes  that  the  presence  of  several  nerves  in  a  part 
coming  from  different  origins,  has  not  for  its  object  the  accumulation  of 
a  great  quantity  of  the  nervous  influence,  but  the  performance  of  seve- 
ral distinct  and  peculiar  functions.  From  these  researches,  we  perceive 
also  how  favourable  are  the  results  to  the  doctrine  of  the  plurality  of  the  . 
nervous  svstem. 


174  OK  THE  NERVOUS  SYSTEM. 

quence  of  the  afflux  of  blood  becoming  the  seat  of  the  ex- 
halation of  coagulating  lymph,  begins  to  swell  in  a  short 
time  after  the  division,  and  forms  a  kind  of  firm,  elongat- 
ed, grayish  nodule;  the  inferior  extremity  presents,  in  its 
turn,  the  same  phenomena  as  the  preceding;  and  as  the  tu- 
mefaction increases,  the  extremities  approximate,  and  are 
finally  agglutinated  together,  by  means  of  the  plastic  sub- 
stance which  they  exhaled.  The  enlargement  which  re- 
sults from  the  junction  of  the  two  nodules  remains  some 
time;  but  it  gradually  diminishes  and  finally  disappears. 
There-union  is  perfectly  re-established  in  about  six  weeks 
or  two  months.  In  this  process,  there  appears  to  be  a  re- 
production of  the  medullary  part  of  the  nerve,  and  several 
anatomists  have  asserted  that  they  have  even  traced  the 
medullary  filaments  into  the  interior  of  the  cicatrix.  What 
proves  this  fact  is,  that  the  cicatrix  acquires  the  conduct- 
ing power  of  the  organs  of  which  we  are  treating,  and  that 
when  submitted  to  the  action  of  nitric  acid,  far  from  being 
decomposed,  it  assumes  more  consistence,  as  is  the  case 
under  similar  circumstances  with  the  nervous  substance. 
The  restoration  of  the  functions  of  a  divided  nerve  does  not 
take  place,  if  the  separation  of  the  extremities  be  too  consid- 
erable, and  where  there-union  is  effected  merely  by  means 
of  cellular  substance.  If,  on  the  contrary,  the  separation  is 
so  inconsiderable  as  scarcely  to  be  perceived,  the  action  of 
transmission  may  take  place,  to  a  certain  degree,  from  one 
part  of  the  nerve  to  the  other,  from  the  moment  the  divi- 
sion has  been  effected.  Inflammation  of  the  nerves  (neuritis) 
appears  to  be  a  more  common  disease  than  is  generally  be- 
lieved; it  is  often  observed  in  oases  of  neuralgia — a  disease 
which,  however,  frequently  presents  no  appreciable  alter- 
ation of  the  nervous  tissue.  It  is  in  part  to  a  sub-inflam- 
matory state  of  these  organs  that  we  must  attribute  their 
softening,  and  the  tuberculous  and  schirrous  tumours,  de- 
signated collectively  by  the  name  of  neuroma.  To  the 
•same  cause  may  also  be  referred  the  cartilaginous  and  osse- 


OF  THE  NERVOUS  SYSTEM. 


ous  metamorphoses  of  the  nerves — a  kind  of  alteration, 
which  is  sometimes,  though  rarely  observed,  and  is  confin- 
ed to  some  insulated  points  of  these  organs. 


ARTICLE    2. 

Of  the  Ganglionic  Nerves. 

Definition. — The  ganglionic  nerves  are  those  which 
constitute,  with  the  ganglia  of  the  second  class,  the  system 
of  the  great  sympathetic  or  trisplanchnic  nerve, — those,  in 
other  words,  which  being  situated  exclusively  within  the 
trunk,  form  with  the  ganglia  just  mentioned,  a  particular 
order  of  nervous  apparatus,  communicating  with  each  other 
and  with  the  spinal  nerves  by  intermediate  branches,  and 
distributing  numerous  ramifications  to  the  arteries  and  the 
organs  of  vegetative  life:  hence,  the  distinction  of  the  nerv- 
ous system  of  organic  life,  given  by  Bichat  to  the  assem- 
blage of  this  apparatus. 

Division. — The  ganglionic  nerves  are  distinguished  into 
three  varieties:  the  first  comprehends  those  which  form 
the  communications  between  the  ganglia,  the  second,  those 
which  are  intermediate  between  the  ganglia  and  the  cere- 
brospinal nerves,  and  the  third,  those  which  are  ramified 
within  the  organs. 

Situation. — The  intermediate  ganglionic  nerves  are 
mostly  situated  upon  the  sides  of  the  vertebral  column, 
parallel  with  its  axis,  and  between  the  double  series  of  the 
lateral  ganglia,  which  extend  from  the  head  to  the  os  coc- 
cygis.  The  others  extend  from  the  lateral  to  the  mesian 
ganglia.  The  ramifications  of  the  second  variety  are 
placed,  most  of  them,  transversely  upon  the  sides  of  the 
vertebral  column,  between  each  lateral  ganglion  and  the 
corresponding  spinal  nerve.  The  situation  of  the  ramifi- 
cations varies  in  each  organ  to  which  they  are  distribut- 


176  OP  THE  NERVOUS  SYSTEM. 

ed;  but,  like  the  preceding,  they  belong  exclusively  to  the 
trunk. 

Conformation. — Considered  as  a  whole,  the  ganglionic 
nerves  by  no  means  exhibit  the  symmetry  of  those  which 
issue  from  the  encephalo-rachidian  masses.  Beclard  has 
justly  compared  the  system  of  the  great  sympathetic  "  to 
a  subterraneous  stem  or  articulated  root  (rhizome,)  which, 
upon  one  side  of  each  bulb  presents  small  roots,  and  upon 
the  other,  small  branches,  all  of  which  are  separated  at 
right  angles,  or  nearly  so." 

As  to  their  peculiar  form,  the  ganglionic  nerves  are  not 
all  alike:  those  of  the  second  variety  are  rounded,  and  re- 
semble, in  this  respect,  the  spinal  nerves:  those  of  the  other 
varieties  are  flattened,  and,  besides,  those  of  the  third  present 
this  peculiar  character,  that  instead  of  diminishing  in  vo- 
lume in  proportion  as  the)''  ramify,  they  augment  or  dimin- 
ish in  different  ways.  All  are  larger  in  the  neighbourhood 
of  the  ganglia  than  in  the  rest  of  their  extent. 

Origin. — Many  anatomists  have  disputed  whether  the 
ganglionic  nerves  arise  from  those  of  the  cerebro-spinal 
system,  with  which,  as  we  have  already  seen,  they  com- 
municate, or  whether  the  ganglia  ought  to  be  regarded  as 
their  centres  of  origin.  Neither  of  these  propositions, 
however,  is  properly  admissible,  for  the  development  of 
the  ganglionic  nerves  is  perfectly  independent  of  that  of 
the  other  parts  of  the  nervous  system;  but  in  applying,  as 
we  have  already  done,  to  the  term  origin,  the  signification 
of  central  extremity ,  we  ought  to  place  it  in  the  ganglia 
of  the  great  sympathetic,  and  consider  the  nerves  which 
pass  from  them  to  the  organs,  as  forming  with  the  first  so 
many  small  nervous  apparatus,  which  communicate  with 
each  other  and  with  the  encephalo-rachidian  nerves.  At  this 
central  extremity,  the  medullary  filaments  of  the  ganglion 
are  continued  with  those  of  the  nerve,  and  moreover,  the 
envelope  of  the  first  being  extended  upon  it,  adds  firmness 
to  their  mutual  adhesion,  and,  bv  covering  the  second  to  a 


OF  THE  NERVOUS  SYSTEM.  177 

small  extent,  gives  it  the  appearance  of  a  part  of  the  gan- 
glion, elongated  in  the  form  of  a  cord. 

Course. — The  ganglionic  nerves  of  the  first  variety  pass 
directly,  and  without  presenting  any  thing  peculiar,  to  the 
cerebro-spinal  nerves.  The  same  arrangement  obtains 
with  regard  to  the  cords  which  form  the  communications 
between  the  ganglia,  and  especially  with  those,  which,  be- 
ing placed  at  each  side  of  the  vertebral  column,  form  with 
these  what  is  called  the  trunk  of  the  great  sympathetic 
nerve.  As  to  the  nerves  which  pass  from  the  ganglia  to 
the  arteries,  and  to  the  different  organs  of  the  head  and 
neck,  and  to  those  of  the  chest  and  the  abdomen,  they  are 
ramified  in  their  course  and  form  more  or  less  intricate 
plexuses,  either  before  they  have  reached  their  destination, 
as  in  the  cardiac  and  solar  plexuses,  or  after  they  have  ar- 
rived upon  the  parietes  where  they  decussate  with  the  fila- 
ments coming  directly  from  the  ganglia.  In  their  course, 
as  well  as  in  the  plexuses,  these  nervous  filaments  are  con- 
nected with  the  ramifications  of  the  encephalic  nerves,  and 
particularly  with  those  of  the  pneumo-gastric. 

Organic  extremity  or  termination. — The  ganglionic 
nerves  (and  we  speak  here  only  of  those  of  the  third  varie- 
ty,) terminate  in  the  parietes  of  the  arteries  of  the  trunk, 
in  the  heart,  the  digestive  canal  and  its  appendages,  and 
in  the  urinary  and  genital  organs. 

Structure. — The  ganglionic  nerves  of  the  first  variety, 
and  even  those  of  the  second,  are  formed  of  small  medullary 
fibres,  and  of  a  neurilemic  envelope,  which  is  more  dense 
at  their  extremities,  where  it  is  sometimes  continuous  with 
the  envelope  of  the  ganglia,  more  thin  and  delicate  at  their 
middle  part,  and  more  intimately  connected  with  the  small 
fibrillar  than  that  of  the  cerebro-spinal  nerves.  These  last 
are  very  difficult  to  be  separated  from  each  other,  and  are, 
moreover,  plunged  into  the  peculiar  grayish  red  substance, 
which  we  have  already  described  as#belonging  to  the  gan- 
glia.    Notwithstanding  the  differences  which  we  have  just 


17S  OF  THE  NERVOUS  SYSTEM. 

pointed  out  between  these  nervesand  those  of  the  cerebro- 
spinal system,  both  resemble  each  other  with  regard  to 
form,  colour  and  structure:  the  branches  which  connect 
the  ganglia  with  the  spinal  nerves,  resemble  these  in  par- 
ticular, and  much  more  in  proportion  as  they  approach 
them.  As  to  the  nerves  of  the  third  variety,  we  can  not 
distinguish  in  them  any  fibrillar,  and  they  appear  to  be 
entirely  formed  of  a  soft  reddish  pulp,  around  which  we 
can  not  demonstrate  the  existence  of  a  neurilema. 

Characters  and  physical  properties. — The  nervous 
cords  which  pass  from  the  ganglia  to  the  cerebro-spinal 
nerves  have  a  whitish  appearance,  are  less  firm  and  resist- 
ing than  these,  and  appear  to  be  destitute  of  elasticity. 
Those  which  connect  the  ganglia  together  are  of  a  grayish 
colour,  have  more  of  the  bulbous  substance,  and  are  some- 
what less  tenacious  and  consistent  than  the  preceding. 
The  ganglionic  nerves  which  are  distributed  to  the  organs 
are,  with  some  very  few  exceptions,  of  a  reddish  colour, 
very  soft  and  brittle. 

Vital  properties  and  functions. — The  nervous  energy 
of  the  ganglionic  nerves  appears  to  be  less  active  than  that 
of  the  cerebro-spinal  nerves,  and  this  in  proportion  as  they 
are  more  frequently  intersected  by  the  ganglia.  In  their 
healthy  state,  this  nervous  power  of  the  ganglionic  nerves 
is  not  manifested,  either  by  sensibility  or  contractility;  but 
in  certain  diseases,  they  are  the  seat  of  a  peculiarly  painful 
affection. 

The  ganglionic  nerves  serve  to  transmit  the  nervous  in- 
fluence to  the  organs  of  the  involuntary  functions,  but  they 
do  not  convey  to  the  ©entre  of  perception  the  impressions 
which  are  received  by  these  organs;  these  being,  under  or- 
dinary circumstances  and  unless  the  action  of  the  nerves 
be  stimulated  by  disease,  arrested  by  the  ganglia.  All  the 
ganglionic  nerves,  at  least  those  of  the  first  two  varieties, 
contribute  to  the  phenomena  of  sympathy,  by  establishing 
communications  between  the  ganglionic  and  the  cerebro- 


OF  THE  NERVOUS  SYSTEM.  179 

spinal  system;  but  it  is  doubtful  whether  they  are,  as  was 
asserted  before  the  time  of  Bichat,  the  essential  organs  of 
the  sympathies.  All  the  nerves  are,  by  reason  of  their  con- 
tinuity, susceptible  of  producing  these  phenomena.  The 
action  of  the  nerves  of  which  we  are  treating,  though  more 
independent  than  that  of  the  cerebro-spinal  nerves,  is,  how- 
ever, subordinate  to  them,  inasmuch  as  it  ceases  as  soon 
as  these  nerves  are  separated  from  the  cerebro-spinal.  The 
nervous  influence,  which  is  transmitted  to  the  ganglionic 
nerves  by  the  centres  above  mentioned,  arrives  in  the  organs 
only  after  it  has  been,  probably,  diminished,  diyided  and 
modified  by  the  ganglia,  which  distribute  it.  It  is,  therefore, 
to  this  character  which  we  attribute  to  the  ganglia  that 
ought  to  be  referred  the  independence  of  the  portion  of  the 
nervous  system  to  which  they  appertain. 

Pathological  Anatomy. — Few  anatomists  have  paid 
attention  to  the  study  of  the  pathological  anatomy  of  the 
ganglionic  nerves.  They  have  been  known  to  be  inflam- 
ed in  cases  of  neuroses  of  the  abdominal  organs,  and  in 
subjects  who  have  died  from  pertussis:  they  are  also  some- 
times affected  with  atrophia  and  hypertrophia,  especially 
when  the  organs  to  which  they  are  distributed  present  the 
same  pathological  conditions. 

Bibliography  of  the  Nervous  System. 

Vicq-d'Jlzyr.  Recherches  sur  la  structure  du  cerveau,  etc, 

dans  les  Mem.  de  l'Acad.  des  Sciences,  1781-83. 
Traite  d'Anatomie  et  de  Physiologie,  gr.  in  fol., 

avec  pi.  Paris,  1786. 
Gall  et  Spurzheim.  Anat.  et  Physiologie  du  systeme  ner- 

veux  en  general,  et  du  cerveau  en  particulier.  Paris* 

1810-19. 
Fr.  Tiedemann.  Anatomie  du  cerveau,  trad,  de  l'allem. 

par  Jour  dan.  Paris,  1823. 
Serres.   Anatom.   comparee  du  cerveau  dans  les  quatre 


ISO  OF  THE  NERVOUS  SYSTEM. 

classes  des  animaux  vertebres,  2  vol.  in  So.  avec  atlas. 

Paris,  1824  et  1826. 
Desmoulins.  Anatomie  des  systemes  nerveux  des  animaux 

a  vertebres,  etc.  Paris,  1S25. 
Rolando.  De  la  veritable  structure  du  cerveau  de  Phomme 

et  des  animaux,  et  des  fonctions  du  systeme  nerveux; 

trad,  de  l'italien  et  insere  dans  le  Journal  Physiol,  ex- 

perim.  torn.  III.  • 
J.  et  Ch.  Wenzell.  De  penitiori  structura  cerebri.  Tubing. 

1812. 
H.  M.  Edwards.  Mem.  sur  la  struct.  el6m.  des  principaux 

tissus  organiques  des  animaux  vertebres.  Paris,  1823. 
Proschaska.  De  structura  nervorum  anat.  in  opera  minora. 
Reil.   Exercitationes  anatomicse  de  structura  nervorum. 

Halle,  1797. 
Pr&vost  et  Dumas.  Mem.  sur  les  phenomenes  qui  accom- 

pagent  la  contraction  musculaire.     (Journal  de  physiol. 

experim.,  torn.  III.) 

In  this  memoir  are  contained  some  very  interesting  de- 
tails upon  the  structure  of  the  nerves,  a  concise  account  of 
which  will  be  found  in  a  note  in  the  third  section  of  this 
chapter. 
Bogros.   Note  sur  la  structure  des  nerfs  (dans  la  Revue 

medec,  mai  1825,  p.  237.) 
Haase.  De  gangliis  nervorum.  Leipsic,  1772. 
Scarpa.  De  nervor.  gangliis  et  plexubus.  Modene,  1779. 
Lobstein.  De  nervi  sympathetici  humani  frabrica,  usu  et 

morbis.  Paris,  1823,  in  4o.  avec  pi. 
Bracket.  Memoire  sur  les  fonctions  du  Systeme  nerveux 

ganglionnaire.  Lyon,  1825, 
Ch.  Bell.  Recherches  anat.  et  physiol.  sur  le  systeme  ner- 
veux (Journal  de  physiol.  experimentale,  torn.  I.  et  II.) 
Bell  on  the  Nerves. 

Legallois.  Experiences  sur  le  principe  de  la  vie.     Paris, 
1812 


OF  THE  NERVOUS  SYSTEM.  181 

Georget.  De  la  physiologie  du  systeme  nerveux.    Paris, 

1821. 
Breschet.  Art.  Acephale,  et  Anencephale  du  Dictionn.  de 

Medecine  en  18  vol. 
Geoffroy-St.  Hilaire.  Philosoph.  anatom.,  torn.  II. 
Pinel  fils.  Recherches  sur  Pendurcissement  du  systeme 

nerveux.  Paris,  1822. 
Lallemand.  Recherches  anatomico-pathologiques  sur  Pen- 

cephale  et  ses  dependences:  quatre  lettres.  Paris,  1820, 

1823. 
Rostan.  Recherches  sur  le  ramollissement  du  cerveux,  2e. 

edit.  Paris,  1823. 
Ollivier  (d'Angers).  Traite  de  la  moelle  epiniere  et  de  ses 

maladies.  Paris,  1823. 
Rochoux.  Recherches  sur  l'apoplexie. 
L.  G.  Descot.  Dissertation  sur  les  affections  locales  des 

nerfs.  Paris,  1822. 
Magendie.  Exper.  sur  les  racinesdes  nerfs  qui  naissent  de 

la  moelle  epiniere  (Journal  de  Physiologie  experimen- 

tale,  torn.  II.) 
Breschet,  M.  Edwards  et  Levasseur.  De  Pinfluence  du 

systeme  nerveux  sur  la  digestion  stomacale  (Arch,  gener. 

deMed.,aout  1823.) 
Wilson  Philipp.  De  Pinfluence  du  galvanisme  sur  la  di- 
gestion, la  respiration,  etc.  (Arch,  gener.  de  Med.,  mai 

1823.) 
Humboldt.   Resultat  d' experiences  sur  les  actions  galva- 

niques,  etc.  (Arch,  gener.  de  Med.,  octobre  1823.) 
Flourens,  Recherches  experimentales  sur  les  fonctions  et 

les  proprietes  du  systeme  nerveux  dans  les  animaux  ver- 

tebres.  Paris,  1824. 


1S2  TEGUMENTARY  SYSTEM. 


CHAPTER  V1H. 

TEGUMENTARY  SYSTEM. 


SECTION  1. 

General  Observations. 

Definition. — The  tegumentary  system  is  composed  of 
a  large  membrane  which  covers  the  entire  surface  of  the 
body,  and  enters  it  so  as  to  line  all  the  cavities  which  com- 
municate with  the  exterior  world. 

Division. — The  tegumentary  system  is  divided  into  two 
secondary  systems,  the  cutaneous  and  the  mucous. 

Situation. — The  teguments  are  placed  upon  the  surfaces 
of  the  animal  which  communicate  more  or  less  directly 
with  exterior  objects:  thus,  after  having  covered  the  whole 
exterior  surface  of  the  body,  it  lines  the  mouth,  the  oeso- 
phagus, the  stomach,  the  intestines,  and  all  the  excretory 
ducts  that  empty  into  them,  the  aerial  passages,  the  nasal 
fossae  and  all  their  sinuses,  and  the  urinary  and  genital  or- 
gans. 

General  conformation. — The  tegumentary  system,  re- 
presents, by  its  situation,  all  the  other  organs  of  the  body, 
and  its  general  form  may  be.  compared  with  that  which  re- 
sults from  the  union  of  two  hollow  cylinders,  which  are 
continuous  by  their  extremities  and  are  separated  at  their 
contiguous  surfaces  by  an  intermediate  substance.  This 
comparison  is  applicable  only  to  the  skin  and  to  the  mu- 
cous membrane  which  extends  from  the  mouth  to  the  anus; 


TEGUMENTARY  SYSTEM.  1S3 

it  will  include,  however,  all  the  teguments,  if  we  add  to 
the  cylinders  which  we  have  just  mentioned,  certain  pro- 
longations or  appendages,  which  are  plunged  in  different 
points  of  the  intermediate  substance,  and  line  the  aerial 
passages,  the  excretory  ducts  of  the  glands,  the  genito- 
urinary organs,  &c. 

Surfaces. — The  tegumentary  membrane  presents  two 
surfaces,  one  of  which  is  free,  the  other  adherent:  the  first, 
which  is  external  to  the  skin,  and  internal  to  the  mucous 
membrane,  is  in  relation  in  a  continuous  or  interrupted 
manner  with  the  substances  that  are  actually  foreign  to  the 
organization.  The  free  surface  presents  small  granular 
eminences,  porous  depressions,  and  horny  or  calcare- 
ous productions,  either  situated  together,  or  scattered  in 
different  points:  the  adherent  surface,  which  is  internal  to 
the  skin,  and  external  to  the  mucous  teguments,  corres- 
ponds immediately  with  the  layer  of  cellular  tissue,  which 
we  described  in  the  first  chapter,  and,  through  the  medi- 
um of  which,  this  surface  is  connected  with  the  subjacent 
organs.  The  adherent  surface  has  small  eminences,  which 
are  more  or  less  prominent  and  correspond  to  the  depres- 
sions on  the  free  surface. 

Structure. — In  the  organization  of  the  teguments,  we 
are  to  consider:  1st,  the  different  layers  of  which  they  are 
composed  and  upon  which  their  form  depends,  and  2d, 
their  small  secretory  organs. 

The  layers  which  form  the  tegumentary  membrane  are 
five  in  number:  they  vary  in  a  very  sensible  manner,  in 
the  different  parts  of  this  organ,  and  especially,  in  its  two 
grand  divisions:  we  shall  enumerate  them  in  pointing  out 
their  most  general  characters. 

1st.  The  dermis  or  chorion  constitutes  the  basis  of  the 
teguments,  is  the  thickest  of  the  layers  of  which  we  are 
treating,  and  is  situated  underneath  them:  it  is  formed  of 
compact  cellular  tissue,  which  permits  numerous  blood  ves- 
sels and  nerves  to  ramify  between  its  fibres. 


1S4  TEGUMENTARY  SYSTEM. 

2d.  The  vascular  retiform  layer,  which  is  placed  upon 
the  dermis,  is  extremely  thin  and  delicate,  and  results  from 
the  interlacement  of  the  small  arteries,  veins  and  lympha- 
tics which  traverse  it. 

3d.  The  small  papillx,  are  formed  by  the  peripheral 
extremities  of  the  nerves  which  traverse  the  preceding 
laminae.  It  is  probable,  that  the  nerves  of  these  small  nerv- 
ous papillae,  which  are  situated  upon  the  surface  of  the 
teguments,  belong,  like  most  of  the  others,  to  the  dermis 
itself;  and  are  only  invested  by  the  extremities  of  the 
nerves  which  traverse  it  with  the  vessels,  and  terminate 
upon  its  surface. 

These  last  two  laminae  are  not  well  marked,  and  ought  to 
be  regarded  rather  as  the  most  superficial  parts  of  the  first. 

4th.  The  rete  mucosum  of  Malpighi  consists  of  a  layer 
of  semi-organized  mucus  which  contains  the  pigment  or 
colouring  matter  of  the  skin,  and  is  situated  between  the 
epidermis  and  the  superficial  laminae  of  the  chorion.  The 
existence  of  the  rete  muscosum,  first  described  by  Malpighi, 
and  since  by  many  anatomists,  has  been  denied  by  Bichat 
and  M.  Chaussier;  while  some,  and  amongst  others,  M. 
Gaultier,  founding  their  opinion  upon  observations  on  the 
skin  of  the  negro,  assert  that  it  consists  even  of  several 
layers. 

5th.  The  epidermis  or  scarf-skin,  is  the  most  superfi- 
cial of  the  tegumentary  laminae,  and  is  by  no  means  dis- 
tinct in  every  part  of  the  system  of  which  wc  are  treating. 
The  epidermis,  considered  by  some  as  formed  of  several 
laminas,  endowed  with  a  certain  degree  of  vitality,  which 
diminishes  progressivel)'  from  the  most  internal  to  the 
most  superficial,  and  by  others,  as  having  a  squamous 
structure,  is  a  whitish,  semi-transparent,  membraniform 
substance,  which  is  moulded  upon  the  prominences  of  the 
chorion,  and  is  generally  regarded  in  the  present  day  as 
destitute  of  life,  and  as  deposited  upon  the  surface  of  the 
teguments  by  an  excretory  process. 


TEGUMENTARY  SYSTEM.  185 

The  small  secretory  organs  that  are  observed  in  thetegu- 
mentary  system  are  known  under  the  names  of folliculi, 
cryptse,  &c.  and  consist  of  a  species  of  very  small,  oblong 
or  rounded  cyst,  terminated  by  a  more  narrow  part, — a 
kind  of  neck,  which  performs  the  office  of  excretory  duct, 
and  opens  upon  the  free  surface  of  the  teguments:  hence, 
the  small  porous  depressions  which  are  observed  upon  this 
surface.  The  follicles  appear  to  result  from  a  simple  de- 
pression of  the  tegumentary  membrane,  and  are  formed  of 
the  same  anatomical  elements,  that  is,  of  a  dense  capsule 
similar  to  the  chorion,  surrounded  and  pervaded  by  nume- 
rous vessels;  of  a  vascular  nervous  net-work  spread  upon 
the  concave  surface  of  the  dermis,  and  of  excretory  parts 
which  vary  according  to  the  kinds  of  follicles,  and  which 
sometimes  contain  a  pigment  or  colouring  matter,  as  that 
which  is  observed  in  the  hairs,  &c.  The  follicles  may  be 
divided,  according  to  the  nature  of  their  secretions,  into  two 
kinds:  the  first  comprehends  those  which  secrete  a  more  or 
less  fluid  substance,  and  carry  it  to  the  surface  of  the  tegu« 
ments:  these  are  the  cryptae  or  the  follicles  properly  so 
called,  whose  secretions  vary  accordingly  as  they  belong 
to  the  skin,  or  to  the  mucous  membranes.  They  occur 
in  every  part  of  the  teguments;  but  they  are  not  every 
where  equally  numerous.  We  find  them  sometimes  in- 
sulated, sometimes  in  groups,  and  sometimes  again  in  regu- 
lar orders.  The  second  is  composed  of  the  follicles  which 
are  designated  more  particularly  under  the  name  of  bulbs, 
and  which  M.  de  Blainville  has  called  phaneres*,  because 
their  secretions,  being  always  solid,  remain  apparent  on 
the  surface  of  the  animal:  these  productions  are,  the  hairs, 
the  nails  and  the  teeth.  The  bulbs  occur  only  in  certain 
parts  of  the  tegumentary  tissue,  and  are  almost  always  col- 
lected in  groups. 

Characters,  physical  and  chemical  properties. — The 

*  From  Qavtfor,  evident,     S.  D.  G, 
25 


186  TKGUiMENTARV  SVSTEJM. 

colour  of  the  tegumentary  membrane  varies  accordingly  as 
it  is  owing  to  the  presence  of  blood  or  to  that  of  pigment; 
there  being  in  this  respect  remarkable  differences  not  only 
between  the  external  and  the  internal  teguments,  (the  latter 
have  no  pigment,)  but  also  between  the  different  parts  of 
the  same  membrane.  The  internal  membranes  also  vary 
in  regard  to  their  density  and  thickness;  but  it  may  be 
said  as  a  general  rule,  that  their  density  is  intermediate  be- 
tween the  cellular  and  the  fibrous  tissues.  The  teguments  are 
susceptible  of  considerable  extension,  after  which  they  re- 
cover their  original  dimensions,  either  suddenly,  or  slowly, 
accordingly  as  the  distension  has  been  ancient  or  recent,  and 
accordingly  as  its  cause  disappears  slowly  or  with  rapidity. 
The  elasticity,  or  rather  the  retractility  of  the  tissue  of 
the  tegumentary  membranes,  is  moreover  rendered  evi- 
dent by  the  rapid  separation  of  the  borders  of  the  solution 
of  continuity,  at  the  moment  of  an  operation. — Exposed  to 
the  action  of  ebullition,  the  chorion  is  almost  entirely  reduced 
to  gelatine,  and  this  principle,  together  with  a  small  quantity 
of  mucus,  appears  to  be  the  principal  ingredient  in  the 
composition  of  the  reticular  body  of  Malpighi.  The  epi- 
dermis is  insoluble  in  water.  M.  Vauquelin  regards  it  as 
indurated  mucus;  Hatchett  as  coagulated  albumen.*  At  the 
commencement  of  putrefaction,  the  subjacent  laminse  to 
the  epidermis  spontaneously  separate;  and  the  epidermis  it- 
self is  detached  a  few  days  after  death  by  the  fluids  which 
transude  through  the  chorion. 

Vital  j)roperties. — The  teguments  enjoy  a  very  active 
vitality.  The  numerous  nerves  which  are  distributed  to 
them  render  them  extremely  sensible,  but  in  such  a  man- 
ner, and  in  such  degrees,  as  vary  greatly  according  to  their 

*  The  human  epidermis  possesses  the  same  properties  as  horn:  it  con- 
sists of — fatty  matter,  0.5;  animal  matter,  soluble  in  water,  5.0;  concrete 
albumen,  93  to  95;  lactic  acid,  lactate,  phosphate,  and  hydrochlorate  of 
potash,  sulphate,  and  phosphate  of  lime,  an  ammoniacal  salt,  andiraees 
of  iron,  1.— John  Ecrits,  Chim.  VI,  92.— S.  D.  G. 


TEGUMENTARV  SYSTEM.  187 

different  parts.  Their  vital  contractility  is  equally  remark- 
able. 

Differences  according  to  age. — Wolff,  Ocken,  and  Mec- 
kel, regarding  the  vitelline  membrane  of  birds  as  analo- 
gous to  the  urachus  of  the  marnmiferi,  are  of  opinion,  that 
the  intestinal  canal  arises  from  the  umbilical  cord  at  the 
beginning  of  the  human  ovum,  and  that  the  tegumentary 
membrane  of  this  canal  exists  before  any  of  the  other  or- 
gans. According  to  the  same  manner  of  observing,  the  in- 
ternal tegument  is  formed  before  the  external.  These  con- 
clusions are  far  from  being  satisfactory,  and  we  possess  as 
yet  no  positive  information  with  regard  to  the  time  in  which 
theformation  of  the  teguments  begins  to  take  place.  It  would 
appear  natural  to  suppose,  however,  that  they  do  not  pre- 
cede in  their  development  the  organs  which  they  are  des- 
tined to  cover:  thus,  the  skin,  which  at  first  forms  onl}-  a 
demi-canal,  is  open  at  its  anterior  surface,  because  the  an- 
terior parietes  of  the  trunk  present  an  interruption  at  the 
same  time.  The  skin  approaches  successively  to  the  mesian 
line,  in  proportion  as  the  parietes  of  the  abdomen  them- 
selves approximate,  so  that  the  interruption  only  ceases 
after  these  are  fully  united.  The  teguments  pass  succes- 
sively from  their  semi-liquid  state  to  their  proper  consist- 
ence. Their  thickness  is  in  direct  ratio  with  the  age  of 
the  individual.  The  differences  which  exist  between  the 
external  and  the  internal  teguments,  scarcely  observable 
in  the  early  stage  of  foetal  life,  become  more  prominent  in 
proportion  as  the  individual  advances  in  life. 

Functions. — The  tegumentary  system  envelops  the  en- 
tire mass  of  the  body,  protects  it  from  external  injuries, 
and  establishes  its  relations  with  the  exterior  world:  1st, 
as  an  organ  of  general  sensibility,  and  of  special  sensations, 
and  2d,  as  an  organ  of  absorption,  and  of  exhalation.  The 
functions  of  this  system  vary  in  the  different  parts  of  the 
body — a  difference  which  results  from  a  difference  in  their 
organization. 


188  TEGl'MENTARY  SYSTEM. 

The  extent  of  the  tegumentary  organ,  and  the  importance 
of  its  functions  render  its  state  of  integrity  of  the  highest 
consequence  to  the  general  health.  The  intimate  sympathy 
which  exists  between  the  different  parts  of  the  teguments, 
renders  it  necessary  to  the  health  of  the  individual,  that 
there  should  be  the  most  perfect  anatomical  and  physiolo- 
gical integrity;  thus,  the  suppression  of  the  cutaneous  ex- 
halation, is  almost  invariably  followed  by  an  increase  of 
exhalation  of  some  of  the  mucous  membranes,  and  this  su- 
perabundance of  activity,  or  rather,  the  humoural  conges- 
tion which  takes  place,  may  be  followed  by  inflammation: 
such  are  the  most  frequent  causes  of  bronchitis,  pneumonia, 
and  some  other  affections. 


section  2. 
Of  the  Skin. 

Definition. — The  skin  is  that  part  of  the  tegumentary 
membrane  which  covers  the  whole  external  surface  of  the 
body. 

Division. — The  external  teguments  consist  of  the  skin 
and  its  appendages,  which  are,  in  the  human  subject,  the 
nails  and  the  hairs. — These  will  be  described  with  the  ap- 
pendages of  the  mucous  membranes  in  the  fourth  section 
of  the  present  chapter. 

Conformation. — The  skin  represents  the  form  of  the 
body  which  it  covers,  enters  into  its  cavities,  such  as  the 
mouth,  the  nostrils,  the  anus,  the  urino-genital  organs,  &c, 
and  becomes  mucous  membrane,  without  interruption  of 
continuity. 

The  skin  often  presents  rugas  or  folds  which  depend 
upon  this  membrane,  which,  not  being  susceptible  of  con- 
tracting as  much  as  the  subjacent  tissues,  becomes  pucker- 
ed so  as  to  accommodate  itself  to  their  retraction,  and  some- 
times, also,  owing  to  the  loss  of  a  portion  of  its  elasticity  in 


TEGUMENT ARY  SYSTEM.  189 

consequence  of  age,  the  membrane  can  not  retract  when 
the  organs  which  it  covers  diminish  in  volume  and  cease 
to  sustain  it.  The  other  folds  are  those  which  are  observ- 
ed upon  the  skin  of  the  articulations,  and  are  the  result  of 
the  intermittent  extension  which  it  experiences  in  conse- 
quence of  the  motions  of  the  joints. 

Surfaces. — The  external  or  free  surface  of  the  skin  is 
in  relation  with  the  exterior  world.  It  is  smooth  and  even, 
especially  in  the  female,  and  is  moistened  by  the  perspira- 
tory and  sebaceous  exhalations.  We  observe  upon  the  free 
surface  of  the  skin,  besides  the  folds  of  which  we  have  al- 
ready spoken,  and  which  extend  through  the  entire  thick- 
ness of  the  membrane,  small  papillary  prominences,  and 
several  kinds  of  depressions.  The  prominences  are  either 
insulated,  or  arranged  in  linear  order,  accordingly  as  their 
direction  varies;  the  most  numerous  and  remarkable  by  the 
regularity  of  their  disposition,  are  those  in  the  palm  of  the 
hand  and  the  sole  of  the  foot.  This  surface  also  presents 
the  orifices  of  the  sebaceous  bursse,  which  are  more  nu- 
merous and  conspicuous  in  the  face,  especially  on  the  wings 
of  the  nose,  than  any  where  else. 

Finally,  the  external  surface  of  the  skin  presents,  in  cer- 
tain parts,  the  excretions  of  the  bulbous  or  phaneric  folli- 
cles, that  is,  the  hairs  and  the  nails. 

The  internal  or  adherent  surface  of  the  skin  is  connected 
with  the  subjacent  parts  by  cellular  tissue,  which  is  either 
loose,  or  very  compact,  accordingly  as  the  skin  is  destined 
to  perform  more  or  less  extensive  gliding  motions.  We 
have  already  seen,  in  a  preceding  part  of  this  work,  that 
there  are  synovial  capsules  interposed  between  different 
organs  and  the  tegumentary  membrane  to  facilitate  their 
motions.  The  skin  is  most  frequently  in  contact  with  the 
adipose  tissue;  sometimes,  however,  it  is  intimately  con- 
nected to  the  fibrous  organs,  and  at  others,  to  the  suhcu- 


190  TEGUMENTARY  SYSTEM. 

taneous  muscles,  which  are  more  generally  found  in  ani- 
mals, and  are  more  important  in  them  than  in  man.* 

The  internal  surface  of  the  skin  presents  numerous,  ob- 
lique, areolar  depressions,  containing  adipose  tissue,  and 
having  their  base  pierced  by  small  foramina,  for  the  passage 
of  blood  vessels  and  nerves:  these  depressions,  which  are  al- 
most invisible  in  some  parts,  as  in  the  dorsal  part  of  the  hand 
and  the  foot,  the  scrotum,  &c,  are  remarkably  large  in  the 
palm  of  the  hand,  the  sole  of  tbe  foot,  the  back,  the  abdo- 
men, &c.  We  observe  also  upon  this  surface,  numerous 
small  prominences,  or  secretory  organs,  which  are  formed 
by  the  base  of  the  follicles  of  this  membrane,  and  appear, 
as  we  have  already  said,  to  result  from  a  depression  of  the 
chorion. 

Structure. — We  shall  here  enter  into  a  more  minute 
detail  with  regard  to  the  laminae  of  which  we  treated  in 
the  preceding  section. 

1st.  The  dermis,  or  the  principal  lamina  of  the  cutaneous 
organ,  is  formed  of  a  peculiar  cellulo-fibrous  tissue,  which 
some  anatomists  have  supposed  to  be  analogous  to  the  mus- 
cular fibre;  but  it  appears  to  result  from  a  modification  of 
the  generative  tissue,  less  characterized  than  that  which 
constitutes  this  fibre.  The  fibrous  structure  of  this  tissue 
is  most  evident  in  the  palm  of  the  hand,  the  sole  of  the 
foot,  and  in  those  parts  where  the  dermis  is  connected  with 
a  layer  of  the  fibrous  tissue:  we  may  then  regard  it  as  the 
most  superficial  part  of  the  fibrous  tissue,  from  which  it  is 
almost  impossible  to  separate  it. 

The  fibres  of  the  dermis  are  indistinct  on  the  greatest 
part  of  the  trunk  and  the  extremities,  nor  are  they  at  all 
distinct  upon  the  dorsum  of  the  hand  and  foot,  the  fore- 
head, &c.  The  tissue  of  the  dermis  is  less  compact  on  its 
internal,  than  upon  its  external  surface,  where  it  is  cover- 

*  The  platysma-myoides  is  the  only  muscle  of  tliis  kind  in  the  human 
subject. — S.  D.  G. 


TEGUMENT ARY  SYSTEM.  191 

ed  by  the  vascular  net-work,  and  presents  the  papillary 
prominences  which  we  have  just  pointed  out  on  the  exter- 
nal surface  of  the  skin,  and  which  are  more  conspicuous 
upon  the  dermis  where  it  is  denuded  of  its  subjacent  laminae, 
which  have  a  tendency  to  obscure  them.  The  internal 
surface  lies  almost  every  where  upon  a  layer  of  adipose 
tissue,  which  varies  in  thickness,  penetrates  the  interstices 
of  the  dermis,  and  contains  a  great  number  of  blood  ves- 
sels and  nerves:  these  insinuate  themselves  into  the  cells  of 
the  dermis,  distribute  filaments  to  its  tissue,  and  terminate, 
most  of  them,  upon  its  external  surface,  where  they  form 
by  their  interlacement  the  second  layer  of  the  skin.  The 
dermis  is  generally  white;  when  its  vessels,  however,  ad- 
mit much  blood,  it  presents  a  faint  red  colour.  It  is  very 
thick  on  the  posterior  part  of  the  trunk,  the  external  sur- 
face of  the  extremities,  the  palm  of  the  hand,  and  sole  of 
the  foot,  upon  the  cranium,  &c;  more  thin  and  smooth  on 
the  anterior  part  of  the  trunk,  the  internal  surface  of  the 
extremities,  the  face,  and  still  more  delicate  on  the  eye- 
lids, the  genital  organs,  the  nipple,  &c  The  thickness  of 
the  dermis  varies  in  these  different  parts  from  about  a  sixth 
to  a  twentieth  of  an  inch.  It  is  supple,  extensible,  and 
retractile.  By  desiccation  it  is  rendered  elastic  like  horn; 
by  the  action  of  ebullition  it  is  resolved  into  gelatine:*  un- 
der the  influence  of  cold,  of  certain  moral  affections,  &c, 
it  exhibits  true  vital  contractions.  The  papillae  upon  the 
external  surface,  appear  to  favour  the  tactile  sensibility  of 
the  skin;  at  least,  they  are  more  developed  where  this  sen- 
sibility is  more  exquisite. 

2d.  The  vascular  retiform  layer  is  merely,  as  we  have 
already  said,  the  external  surface  of  the  dermis,  and  not  a  dis- 

*  It  is  the  gelatinous  nature  of  the  chorion  which  renders  it  fit  for  the 
purposes  of  the  arts.  In  effect,  the  gelatine  combines  with  the  tanin, 
and  forms  an  insoluble  compound,  which  the  tanner  obtains  by  putting 
the  dermis  in  contact  with  different  kinds  of  bark  (those  of  the  oak,  the 
fir,  &c.,)  which  contain  the  principle  to  which  we  have  just  alluded. 


192  TEGUMENTARY  SYSTEM. 

tinct  layer.  Notwithstanding  this,  it  is  well  developed  in 
those  parts  where  there  is  constantly  a  bright  florid  colour, 
as  in  the  cheeks,  and  enjoys  there  a  kind  of  erection,  as  is 
proved  by  some  of  the  moral  affections. — It  is  this  part  of 
the  skin  which  is  the  true  seat  of  the  cutaneous  exhalation 
and  absorption. 

3d.  The  small  papillse,  are  also  indistinct  from  the  su- 
perficial part  of  the  dermis:  they  are  situated  on  the  exter- 
nal surface  of  the  dermis,  and  are  in  part  composed  of  the 
vascular  retiform  layer.  The  sense  of  touch  being  in  di- 
rect ratio  with  the  number  of  these  small  prominences, 
it  is  supposed  that  the  nervous  substance  is  more  abundant 
there,  than  in  the  other  parts  of  the  skin;  this,  however, 
can  not  be  demonstrated. 

4th.  The  rete  mucosum,  which  has  eluded  the  observa- 
tions of  Bichat  and  Chaussier,  notwithstanding  the  most 
minute  dissections,  is  spread,  as  is  asserted  by  those  who 
have  seen  it,  under  the  form  of  a  mucous  lamina,  upon  the 
preceding  parts,  and  is  moulded  exactly  upon  the  papillae. 
This  lamina,  which  is  the  seat  of  the  colour  of  the  skin,  is 
much  more  conspicuous  in  proportion  as  the  colour  is  more 
prominent.  It  is  generall}7  regarded  as  a  simple  lamina,  but 
several  anatomists,  and  particularly  M.  Gaultier,  assert  that 
it  consists  of  several  layers.  This  physiologist,  drawing  his 
conclusions  from  a  number  of  experiments  performed  upon 
the  skin  of  the  Negro,  asserts  that  the  rete  mucosum  con- 
sists of  four  laminae:  the  internal  is  vascular,  and  secretes  the 
colouring  matter  of  the  skin;  the  second,  placed  imme- 
diately upon  the  first,  is  white,  inorganic,  and  is  termed 
albuginea  'profunda;  the  third  is  composed,  like  the  first, 
of  small  arteries  and  veins  united  in  clusters,  and  is  im- 
pregnated with  the  colouring.matter  of  the  skin;  the  fourth, 
or  the  albuginea  super Jicialis,  is  inorganic  like  the  second, 
is  secreted  by  the  third,  and  covered  by  the  epidermis. 
M.  Dutrochet  admits  the  existence  of  the  last  three  of  these 
laminae,  and  regards  the  first  as  identical  with  the  vascular 


TEGUMENT ARY   SYSTEM.  193 

retiform  layer  on  the  surface  of  the  dermis.  Be  this, 
however,  as  it  may,  the  colouring  matter  of  the  skin,  lo- 
cated by  many  anatomists  in  the  dermis,  and  especially  in 
the  epidermis,  is  really  intermediate  to  these  two  laminae, 
without  their  being,  however,  completely  foreign  to  it. 
This  matter,  called  pigmentum  nigrum,  is  disseminated 
throughout  the  rete  mucosum  under  the  form  of  globules: 
it  may  be  separated  by  long  maceration,  which,  in  dissolv- 
ing the  semi-organized  mucus  in  which  it  is  plunged, 
separates  it  without  alteration.  These  experiments  have 
been  made  only  upon  the  skin  of  the  negro:*  that  of  the 
European,  contains  but  little  of  the  pigmentum  nigrum; 
and  in  the  Albinoes,  it  is  entirely  wanting.  The  thickness 
and  consistence  of  the  rete  mucosum  are  in  direct  ratio  with 
the  quantity  of  this  matter:  it  is  almost  entirely  composed 
of  carbon,  and  appears  to  be  of  use  in  defending  the  ex- 
ternal teguments  fror/i  the  rubific  action  of  caloric,  by  ab- 
sorbing its  rays,  and  preventing  them  from  entering  the 
small  papillae:  the  Albinoes,  therefore,  are  very  sensible  to 
the  impressions  of  the  solar  rays,  even  sometimes  to  such  a 
degree  as  to  produce  the  vesication  of  their  skin. 

5th.  The  epidermis,  the  most  superficial  laminse  of  the 
skin,  is  a  very  delicate  membranous  layer,  which  is  per- 
fectly moulded  upon  the  preceding,  and  adheres  to  them 
intimately,  first,  by  the  hairs  which  traverse  it;  and  which 
it  furnishes  with  a  cortical  expansion;  and  secondly,  by  the 
small  filaments  which  are  perceived  between  the  epider- 
mis and  the  chorion,  after  they  have  been  detached  by  pu- 
trefaction, or  by  immersion  in  boiling  water.  These  fila- 
ments have  been  hypothetically  regarded  by  some  anato- 

*  In  the  negro,  the  rete  mucosum  may  be  deprived  of  its  black  pig- 
ment, by  immersing'  the  foot  or  hand  for  some  time  in  water  impregnat- 
ed with  chlorine  gas:  in  a  few  days,  however,  the  original  colour  will  re- 
turn with  all  its  former  intensity.  This  experiment  was  first  made  by 
Dr.  t3eddoes,  and  has  since  been  repeated  by  many  physiologists. 

S.  D.  G. 
26 


194  TEGUMENTARY  SYSTEM. 

mists  as  exhalent  and  absorbent  vessels.  Beclard  has  just- 
ly thought  that  we  might  consider  them  as  mucous  tractus, 
formed  by  the  intermediate  substance  between  the  chorion 
and  the  epidermis,  and  rendered  more  fluid  by  the  incipient 
stage  of  decomposition. 

The  epidermis  covers  the  entire  surface  of  the  skin, 
like  a  kind  of  dry  varnish,  and  penetrates,  by  becoming 
more  thin  and  delicate,  into  the  sebaceous  and  phaneric 
follicles.  The  structure  of  the  epidermis  has  been  a  cause  of 
much  dispute  amongst  anatomists.  While  some,  as  M.  Mo- 
zou,  of  Turin,  Mascagni,  Gaultier,  and  others,  have  attri- 
buted to  it  a  more  or  less  intricate  organization;  others  have 
supposed  that  it  is  composed  of  scales,  which  are  arranged 
so  as  to  overlap  each  other;  but  neither  of  these  opinions, 
however,  appears  to  be  well  founded.  M.  de  Humboldt,  who 
examined  the  epidermis  with  a  very  powerful  microscope, 
was  neither  able  to  detect  the  vessels  of  which  some  phy- 
siologists have  asserted  it  was  formed,  nor  the  least  appear- 
ance of  organization.  The  epidermis  appears  to  be  a  con- 
crete substance  exhaled  upon  the  surface  of  the  rete  muco- 
sum,  or,  if  we  wish,  the  most  external  part  of  it. 

Is  the  epidermis  porous?  This  we  might  at  first  sight  be 
induced  to  believe,  by  looking  at  the  drops  of  sweat  which 
are  discharged  from  certain  points  of  this  layer,  and  which 
are  depressed  so  as  to  assume  the  appearance  of  perfora- 
tions, and  which  are,  moreover,  much  more  transparent 
than  the  parts  which  separate  them,  if  a  portion  of  epider- 
mis be  placed  between  the  eye  and  the  light.  Leuwenhceck 
believed  in  the  existence  of  these  perforations;  Bichat 
thought  that  they  were  oblique,  and  that  in  consequence 
of  this  only  they  were  imperceptible;  but  repeated  obser- 
vations, and  amongst  others,  those  of  M.  de  Humboldt,  do 
not  justify  this  opinion;  nor  can  there  beany  pores  dis- 
covered either  by  inspection  or  direct  experiments,  and 
the  epidermis  appears  only  to  be  more  thin  and  delicate  in 
the  points  to  which  we  have  just  alluded  than  any  where 


TEGUMENT ARY  SYSTEM.  195 

else.  Besides  this  difference  of  thickness,  common  to  the 
epidermis  on  every  part  of  the  surface  of  the  body,  we  shall 
find  that  there  are  others,  if  we  compare  this  layer  in  the 
different  regions;  thus,  it  is  more  thick  in  the  palm  of  the 
hand,  and  especially  in  the  sole  of  the  foot, — a  difference 
which  ought  not  to  be  attributed  exclusively  to  the  con- 
stant pressure  which  these  parts  experience,  because  it  ex- 
ists already,  though  in  an  inferior  degree,  in  the  foetus. 
Wherever  the  epidermis  is  very  thick  and  firm,  it  appears 
to  be  composed  of  several  laminae:  it  is  white  in  the  Eu- 
ropean, grayish  in  the  Negro,  semi-transparent,  supple, 
and  less  elastic  than  the  chorion,  and  this  in  direct  ratio 
to  the  humidity  which  penetrates  it.  The  epidermis  is 
faintly  hygrometric,  and  by  immersing  it  in  water,  it  be- 
comes opake  and  thickened, — changes  which  take  place 
more  rapidly  when  this  fluid  is  hot.  It  resists,  for  a  long 
time,  the  putrefactive  process,  and  completely  the  action 
of  ebullition:  by  treating  it  with  the  nitric  acid,  it  becomes 
yellow,  and  is  afterwards  reduced  to  a  pulpy  substance;  and 
by  exposing  it  to  the  action  of  the  salts  of  potash  and  soda,  it 
is  converted  into  saponaceous  compounds.  These  chemi- 
cal characters  have  induced  anatomists  to  regard  it  as  an  al- 
buminous substance.  The  epidermis  is  completely  destitute 
of  vitality,  and  enjoys  a  mere  mechanical  character  in  the 
organization,  in  diminishing,  by  its  interposition  between 
the  dermis  and  surrounding  bodies,  the  impressions  of  these 
upon  the  nervous  part  of  the  skin.  Notwithstanding  its 
feeble  hygrometricity,  the  epidermis  gives  passage  to  the 
perspiratory  fluids,  and  allows,  to  a  certain  extent,  foreign 
substances,  either  liquid  or  gaseous,  to  enter  the  system. 

The  skin  is  supplied  with  a  great  number  of  sebaceous 
and  bulbous  follicles:  we  shall  speak  of  the  latter  when  treat- 
ing of  the  solid  parts  which  they  produce.  As  to  the  first, 
we  do  not  know  whether  they  are  spread  throughout  the 
whole  extent  of  the  skin:  be  this,  however,  as  it  may,  they 
occur  in  great  number  on  the  face,  around  the  alae  nasi,  in 


19G  TEGUMENTARV  SYSTEM. 

the  groins  and  axilla?,  around  the  anus  and  on  the  most 
hairy  parts  of  the  body.  The  sebaceous  follicles  are,  as 
we  have  already  said,  very  small  vesicles  which  open  on 
the  surface  of  the  skin,  are  destitute  of  epidermis,  and  ap- 
pear to  result  from  the  simple  depressions  of  this  mem- 
brane. They  secrete  an  unctuous  substance,  which  often 
accumulates,  becomes  inspissated,  and  may  be  discharged 
by  pressure,  under  the  form  of  small  worms:  in  the  meatus 
auditorius  externus  this  fluid  is  termed  cerumen.*  This 
unctuous  fluid  protects  the  skin  from  the  action  of  the  fluids 
applied  upon  its  surface,  and  performs,  in  this  respect,  the 
same  character  as  the  epidermis. 

Characters,  physical  and  chemical  properties. — The 
different  lamina?  which  compose  the  skin,  constitute,  by 
their  union,  a  membrane  whose  colour  varies  according  to 
the  different  races  of  the  human  family,  from  white  to 
black,  passing  through  all  the  intermediate  grades;  being 
supple,  elastic,  more  thick  in  people  of  colour  than  in  the 
European,  and  being  with  difficulty  penetrated  by  the  fluids 
which  are  in  contact  with  its  free  surface,  and  composed 
in  great  measure  of  gelatine  and  a  certain  quantity  of  albu- 
minous mucus. 

Vital  properties. — The  skin  enjoys  an  exquisite  sensi- 
bility, which  is  owing  to  the  great  number  of  nerves  which 
are  spread  upon  the  external  surface  of  the  dermis,  and  is 
more  conspicuous  in  those  parts  where  the  papilla?  are 
very  numerous,  and,  caeteris  paribus,  in  those  where  the 
epidermis  and  the  rete  mueosum  are  thinner  than  in  the 
other  parts.  The  external  tegument  is  susceptible  of  very 
sensible  vital  contractions,  which  give  it  the  peculiar  ap- 
pearance vulgarly  known  by  the  name  of  wrinkles. 

Differences  according  to  age  and  sex. — The  skin  is  not 

*  According-  to  Vauquelin,  the  cerumen  cf  the  ear  is  composed  of  the 
following1  ingredients:  1st,  albumen;  2d,  an  inspissated  oil;  3d,  a  colour- 
ing' matter;  4th,  soda;  5th,  phosphate  of  lime. — F„ourcroy,  ix.  373. 

S.  D.  G. 


TEGUMENT ARY  SYSTEM.  197 

distinct  until  about  the  end  of  the  second  month  of  pregnan- 
cy, at  which  period  the  epidermis  is  already  visible.  At 
first  the  skin  is  destitute  of  colour,  and  of  such  tenuity  as 
to  render  it  perfectly  transparent,  but  it  soon  assumes  the 
faint  red  colour  which  it  exhibits  at  birth.  The  sebaceous 
cryptae  appear  at  half  the  term  of  uterine  life;  during  the 
whole  period  of  which,  the  external  surface  of  the  skin, 
being  in  contact  with  the  amniotic  fluid,  is  covered  by  an 
unctuous  layer.  As  we  advance  in  age,  the  skin,  which  at 
birth  is  nearly  of  the  same  colour  in  all  the  different  races, 
assumes  the  characteristic  and  distinctive  colour  of  each. 
The  colour  of  the  skin  is  first  observed  on  the  genital  or- 
gans, around  the  nipple,  the  eyes,  the  nails,  and  finally,  at 
the  end  of  the  first  week,  it  extends  over  the  whole  body. 
This  membrane,  which  is  very  delicate  and  smooth  in  the 
infant,  becomes  more  thick  and  consistent  as  the  individual 
advances  in  life.  In  the  male,  it  becomes  dry,  and  loses  its 
retractility  with  age;  while,  in  the  female,  it  retains  almost 
entirely  the  delicacy  and  smoothness  which  it  possessed  in 
infancy. 

Functions. — The  skin  is  the  organ  of  the  tactile  sensa- 
tions and  of  touch.  It  exhales  two  kinds  of  fluid,  which 
are  eliminated  by  its  free  surface;  the  one  is  the  sebaceous 
fluid  which  we  have  already  described;  the  other  is  more 
thin  and  is  continually  discharged  under  the  form  of  va- 
pour, and  sometimes  under  that  of  fluid,  constituting  what 
is  termed  sweat:  this  fluid  is  probably  discharged  through 
the  points  of  the^epidermis,  which,  in  consequence  of  their 
thinness,  have  been  considered  by  some  physiologists  as 
pores.  The  cutaneous  vapour  or  insensible  perspiration  is 
remarkably  abundant,  and  is,  in  this  respect,  to  the  pul- 
monary transpiration,  as  eleven  to  seven:  it  contains  car- 
bonic acid  gas  and  an  odorous  animal  principle.  When  it 
becomes  too  abundant  to  evaporate  on  the  surface  of  the 
skin,  and  is  presented  under  the  form  of  small  drops,  its 
composition  appears  to  be  somewhat  different  and  more 


198  TEQTTMENTARY  SYSTEM. 

complex.*  According  to  the  analysis  of  M.  Berzelius, 
sweat  is  composed  of  the  hydrochlorate  of  potash  and  soda, 
of  the  lactic  acid,  the  tartrate  of  soda,  and  a  small  proportion 
of  animal  matter.  The  sweat  emits  a  peculiar  odour  which 
differs  in  different  individuals,  and  is  stronger  in  infancy 
than  at  any  other  period.  There  are  some  facts  which 
would  induce  us  to  believe  that  the  subcutaneous  fat  is  also 
exhaled  by  traversing  the  skin,  if  not  constantly,  at  least 
when  the  temperature  of  the  body  is  considerably  elevated. 
The  skin  absorbs,  but  slowly  and  in  small  quantities,  the 
fluids  which  are  put  in  contact  with  it;  so  that  it  is  impro- 
per to  regard  it  as  an  important  organ  of  absorption.  The 
small  degree  of  permeability  of  the  epidermis  presents  an 
obstacle  to  this  function,  which  is  exceedingly  active  when 
the  epidermis  is  removed.  In  man,  the  skin  can  scarcely 
be  considered  as  an  organ  of  defence;  though  it  performs 
this  function  by  means  of  its  epidermic  layer,  the  hairs 
and  the  nails. 

Pathological  Anatomy. 

When  the  skin  suffers  considerable  and  long  continued 
distention,  as  happens  during  pregnancy,  the  fibres  of  the 
dermis  are  not  only  elongated  and  separated,  but  some  of 
them  are  actually  torn.  When  the  membrane  recovers  its 
original  state,  these  fibres  cicatrize:  hence  the  white  strias 
which  are  constantly  found  on  the  skin  of  the  abdomen  of 
women  who  have  had  children.  Another  effect  of  distention 
is  the  production  of  folds  and  wrinkles,  which  vary  in  size 
according  to  the  degree  of  elasticity  of  the  skin,  and  conse- 
quently, also,  according  to  the  age  of  the  individual. 

*  Perspiration,  whether  sensible  or  insensible,  is  a  very  important 
means  of  depuration,  the  suppression  of  which  produces  some  of  the 
most  fatal  diseases.  It  has  for  its  object  the  equilibrium  of  the  tempe- 
rature of  the  body,  by  carrying  off  the  superabundance  of  caloric  which 
protects  the  system:  so  that  those  persons  who  perspire  but  little  are 
more  frequently  affected  with  head-aches  than  others. 


TEGUMENTARY  SYSTEM.  I#9 

The  free  surface  of  the  teguments  often  presents  different 
kinds  of  growths,  which  vary  both  in  volume  and  form. 
They  are  generally  termed  warts,  and  are  most  frequently 
seated  in  the  dermis,  of  which  they  are  merely  an  unnatu- 
ral development:  the  secondary  syphilitic  affections  ap- 
pear rather  to  be  seated  in  the  vascular  retiform  lamina, 
than  in  any  other  part  of  the  dermis.  The  horny  produc- 
tions of  the  skin,  of  which  there  are  several  varieties,  are 
sometimes  met  on  the  tissue  of  the  subcutaneous  cicatrices: 
they  have  also  been  known  to  arise  from  the  sebaceous 
follicles;  but  the  most  common  are  those,  which,  in  con- 
sequence of  continual  pressure,  are  formed  in  the  epider- 
mis, or  rather  they  are  a  preternatural  development  and 
harding  of  the  epidermis.  In  this  manner  are  corns  pro- 
duced, which  are  small,  hard,  rounded,  horny  elevations, 
and  which,  being  placed  at  first  on  the  surface  of  the  der- 
mis, create  the  most  severe  pain  by  compressing  the  vascu- 
lo-nervous  layer,  sinking  often  in  its  thickness  and  even  in 
the  subjacent  tissues.  When  the  sebaceous  matter  collects 
merely  in  small  quantities,  the  excretory  ducts  of  the  folli- 
cles of  this  name  present  a  black  appearance,  and  the  mat- 
ter may  be  readily  discharged  by  means  of  pressure.  When 
the  accumulation  becomes  more  considerable,  the  orifice  of 
the  follicles  still  remains  open,  and  the  small  tumour  which 
results  is  termed  a  pimple;  but  if  it  enlarges,  and  the  ori- 
fice becomes  obliterated,  the  pimple  forms  one  of  the  kinds 
of  wen  known  under  the  names  of  meliceres,  steatoma, 
and  atheroma,  names  which  refer  to  a  single  disease,  and 
are  merely  expressive  of  the  nature  and  consistence  of  the 
matter  which  the  wen  contains,  and  accordingly  as  it  may 
be  compared  to  honey,  suet,  or  a  kind  of  soft  pultacious 
substance. 

In  protracted  diseases  accompanied  with  marasmus,  the 
skin  appears  to  participate  in  the  general  decay,  and  pre- 
sents a  remarkable  rugoseness,  a  disagreeable  sallow  aspect, 
which  is  very  common  in  phthisical  persons.  It  also,  some- 


200  TEGUMENTAKY  SYSTEM. 

times,  appears  to  be  affected  with  a  kind  of  local  hypertro- 
phia,  in  consequence  of  prolonged  irritation. 

The  solutions  of  continuity  of  the  skin  are  re-united 
either  immediately  in  consequence  of  the  effusion  of  co- 
agulating lymph,  or  by  the  formation  of  a  new  tegumenta-  . 
ry  membrane  on  the  denuded  surface.  When  a  portion  of 
skin  has  been  removed,  the  cellular  tissue  becomes  the  seat 
of  the  cicatrization,  the  whole  process  of  which  may  be  ob- 
served to  take  place  in  the  same  manner  as  we  have  describ- 
ed in  the  first  chapter.  When  the  cicatrization  is  completed, 
the  skin  is  replaced  by  a  tissue  sufficiently  analogous  to 
its  own,  but  which  differs,  however,  in  some  respects,  and 
is  always  readily  distinguished.  In  effect,  this  tissue  is  more 
dense,  and  less  vascular  than  the  original;  has  generally  no 
papillae,  though  its  external  surface,  which  is  ordinarily 
smooth  and  polished,  presents,  sometimes,  honeycomb-like 
(ganfries)  inequalities.  As  to  the  colour  of  the  cicatrices, 
it  is  more  pale  than  that  of  the  skin  in  the  European;  but 
in  the  negro  it  is  at  first  of  a  white  reddish  colour,  and  gra- 
dually converges  into  that  of  the  neighbouring  teguments 
which  it  is  finally  confounded. 

When  the  epidermis  alone  has  been  removed,  it  is  speedi- 
ly reproduced,  unless  the  subjacent  laminae  are  so  much 
irritated  as  to  suppurate,  a  circumstance  which  materially 
retards  the  formation  of  the  new  epidermis,  and  may  even 
modify  it  in  such  a  manner  as  to  give  it  the  appearance  of 
a  new  tegument. 

Inflammation  of  the  skin  assumes  a  variety  of  forms, 
according  to  the  part  in  which  it  is  seated;  its  intensity,  its 
cause,  the  nature  of  its  secretion,  6cc.  Hitherto,  physicians 
have  paid  but  little  attention  to  the  study  of  the  anatomi- 
cal characters  of  the  cutaneous  phlegmasia^;  their  exterior 
forms  have  almost  alone  been  observed;  and  it  is  after 
these  and  an  often  hypothetical  etiology,  that  they  have 
■fied  this  order  of  diseases.  It  is  on  this  account,  there- 


TEGUMENTARY  SYSTEM.  201 

fore,  that  we  possess  no  satisfactory  information  with  re- 
gard to  their  true  pathological  anatomy. 

The  erythematous  inflammations  of  the  skin,*  that  is, 
those  which  constitute  erysipelas,  the  irruptions  of  scarla- 
tina, the  first  stages  of  a  burn,  the  action  of  rubefacients 
and  of  vesicatories,  are  characterized  by  a  vascular  injec- 
tion, which  affects  either  the  superficial  laminae,  or  the  en- 
tire thickness  of  the  skin,  and  remains  evident  during  life 
by  its  bright  red  and  sometimes  purple  colour,  and  by  the 
uncircumscribed  swelling  of  the  affected  organ.  When 
the  inflammation  is  slight,  the  redness  disappears  upon 
pressure,  and  returns  as  soon  as  the  cause  is  removed;  the 
disease  is  dispersed,  and  the  epidermis  falls  off  in  furfura- 
ceous  scales;  or,  if  the  patient  dies  in  consequence  of  other 
accidents,  there  is  not  the  least  discoverable  trace  of 
phlegmasia.  When,  however,  the  disease  is  more  intense, 
the  dermis,  (and  chiefly  its  most  superficial  parts)  is  pene- 
trated by  a  great  quantity  of  blood,  becomes  swollen  and 
bright,  and  exhales  a  yellowish  serous  fluid,  or  pus,  accord- 
ing as  the  inflammatory  state  is  more  or  less  intense  or 
protracted.  It  is  this  which  is  observed  especially  in  the 
cutaneous  inflammations  brought  on  by  vesicatory  medica- 
ments; the  first  effect  of  the  inflammation  which  they  occa- 
sion is  the  secretion  of  serum,  which  raises  the  epidermis; 
hence,  phlyctaenae  and  blisters.  The  epidermis  breaks 
spontaneously  or  artificially,  falls  off  in  shreds,  and  ex- 
poses the  inflamed  dermis,  whose  secretion  now  becomes 
purulent.  In  cases  where  the  inflammation  is  intense  or 
protracted,  it  leaves  traces  after  the  death  of  the  individual, 
that  is,  the  dermis  is  more  or  less  injected,  thickened  and 
indurated  in  the  dead  body,  and  is  sometimes  penetrated,  and 
as  it  were  combined  with  the  blood  which  fills  its  vessels: 
in  certain  cases,  the  cells  of  the  dermis  are  filled  with  a 
gelatinous  fluid,  and  its  most  internal  ones  are  deprived  of 

*  From  tpiQtftx,  ruber. 
27 


202  TEGUMENTARY   SYSTEM. 

the  fat  which  the}'  contained,  by  the  intensity  of  the  in- 
flammation. Finally,  the  subjacent  cellular  tissue  becomes 
generally  cedematous,  and  sometimes  even  inflamed  and 
penetrated  by  a  purulent  fluid  (phlegmonous  erysipelas). 
The  cutaneous  inflammations  often  terminate  in  gangrene, 
especially  when  they  have  been  very  intense  or  brought  on 
by  aseptic  cause:  in  this  case  the  surface  of  the  affected 
skin  presents  a  livid  or  purple  colour,  and  is  surrounded 
by  a  yellowish  tint;  it  is  now  covered  by  pblyctsenae,  and 
after  these  have  broken,  the  denuded  dermis  exhibits 
small  gangrenous  spots,  which  invade,  in  the  course  of  a 
few  hours,  a  more  or  less  considerable  extent  of  the  affect- 
ed part,  and  even  of  the  subjacent  tissues.  Scarifications 
of  the  skin,  performed  with  the  view  of  discharging  exces- 
sive cedematous  infiltrations,  very  readily  and  frequently 
bring  on  gangrene.* 

We  ought  also  to  refer  to  the  gangrenous  inflamma- 
tions of  the  skin,  the  disease  called  authrax,  a  circumscrib- 
ed inflammation,  which  is  owing  to  a  peculiar  contagious 
agent,  and  is  characterized  by  the  presence  of  a  hard,  red- 
dish, homogeneous,  gangrenous  eschar,  situated  in  the 
thickness  of  the  skin,  and  having  a  tendency  to  extend  by 
invading  the  adjacent  tissues.  The  skin  of  the  part  affect- 
ed is  livid,  cedematous,  and  has  a  number  of  small  blisters 
upon  its  surface,  which  contain  a  kind  of  sanious  fluid. 

Furunculi  are  also,  according  to  the  common  opinion,  a 
cutaneous  gangrenous  inflammation,  characterized  by  the 
presence  of  a  whitish  eschar  termed  the  ventriculns  furun- 
culi, (bourbillon)  which  is  situated  in  the  dermis,  or  even 
in  the  subcutaneous  cellular  tissue,  and  results  from  the 

*  It  appears,  according-  to  the  observations  of  M.  Andral,  Jr.,  that 
venous  congestion  of  the  dermoid  tissue  is  sufficient  to  bring-  on  gan- 
grene, when  the  skin  is  very  slightly  inflamed,  or  even  when  it  exhibits 
not  the  least  sign  of  phlegmasia,  as  was  observed  by  this  author  in  some 
diseases  of  the  heart  where  the  difficulty  of  the  venous  circulation  was 
excessive. 


TEGUMENTARY   SYSTEM.  203 

mortification  of  a  portion  of  skin  or  of  the  cellular  tissue, 
which  has  heen  strangulated  in  consequence  of  the  inflam- 
mation and  swelling  of  the  surrounding  parts. — It  seems 
difficult  to  admit  the  gangrenous  nature  and  strangulation 
of  the  ventriculus  furunculi;  for  as  M.  Gendrin  observes, 
it  does  not  present  the  characters  of  the  eschars  of  the  cel- 
lular tissue,  and  it  occurs,  moreover,  when  the  inflammation 
and  swelling  are  so  slight,  as  to  be  unable  to  occasion  the 
pretended  strangulation  to  which  we  have  just  alluded.  It 
is  more  probable  that  the  ventriculus  of  furunculi  and  of 
authrax,  results  from  a  peculiar  secretion,  which  is  de- 
posited into  the  areolae  of  the  dermis. 

The  skin  is  often  affected  with  peculiar  acute  inflamma- 
tions, which  are  characterized  by  the  development  of  more 
or  less  numerous  pustules,  and  are  chiefly  confined  to  the 
different  kinds  of  variola,  vaccina,  and  rubeola. 

The  pustules  of  the  genuine  variola  occupy  the  thickness 
of  the  dermis,  which  is  of  a  red  colour  around  their  circum- 
ference, and  is  sometimes  infiltrated  with  serum:  during 
their  stage  of  development,  they  present  a  flattened  um- 
bilical form,  and  an  areolar  spongy  disposition.  If  the 
pustules  now  become  dry  and  detached,  they  generally 
leave  no  trace  of  a  cicatrix,  or  at  all  events  it  is  small  and 
superficial,  as  in  the  distinct  variet}7-  of  small-pox,  where 
the  pustules  are  insulated  and  not  very  numerous.  When 
the  pustules,  however,  pass  to  the  suppurative  stage,  their 
base  is  converted  into  a  small  ulcer  which  leaves  a  depress- 
ed reddish  cicatrix,  which  is  more  red  at  first,  but  finally 
becomes  more  pale  than  the  surrounding  teguments:  this 
forms  the  confluent  variety  of  small-pox  in  which  the  pus- 
tules are  exceedingly  numerous  and  approach  each  other, 
and  finally  coalesce;  the  skin  is  swollen,  often  cedematous, 
and  presents  sometimes  gangrenous  points.  Before  the 
pustules  of  small-pox  suppurate,  they  contain  a  limpid  se- 
rous fluid,  which  by  degrees  becomes  more  thick  and  as- 
sumes a  whitish  appearance.     This  disease  may  be  com- 


201  TEGUMENTARY  SYSTEM. 

municated  by  inoculation.  When  the  pustules  are  conical 
or  flattened,  are  situated  merely  upon  the  superficies  of  the 
dermis,  and  leave  no  cicatrices,  they  constitute  the  pseudo- 
variolic  or  varicellic  eruptions,  and  the  varioloid  or  modi- 
fied small-pox  of  vaccinated  subjects,  and  of  those  who  have 
had  the  genuine  variola. 

Inoculation  with  vaccine  matter  by  means  of  a  lancet  in- 
troduced under  the  epidermis,  is  followed  by  the  develop- 
ment of  a  round  pustule,  sunk  within  the  epidermis,  pro- 
jecting upon  the  surface  of  the  skin,  depressed  in  its  cen- 
tre, and  surrounded  by  a  red  areola.  This  pustule  contains 
a  limpid  serous  fluid,  disseminated  through  small  cells 
which  are  separated  by  radiating  and  concentric  septa. 
After  a  certain  length  of  time  it  dries,  is  converted  into  a 
crust,  and  retains  its  circular  and  umbilical  form;  when  it 
falls  off  it  leaves  a  superficial  and  dotted  cicatrix,  which  is 
more  red  at  first,  but  gradually  becomes  whiter  than  the 
surrounding  skin.  When  the  vaccine  matter  has  been  bad, 
the  puncture  is  followed  by  the  development  of  a  simple 
vesicle,  destitute  of  an  areola,  having  a  small  tubercular 
eminence,  and  disappearing  without  a  trace  of  the  punc- 
ture. In  subjects  that  have  been  vaccinated,  the  vaccine 
inoculation  frequently  produces  pustules,  which  differ 
merely  from  the  true  pustules  by  their  situation  upon  the 
surface  of  the  dermis;  the  fluid  which  they  contain  being 
proper  for  vaccination. 

In  rubeola,  the  vascular  retiform  lamina  of  the  dermis, 
presents  a  phlogose  appearance  around  the  pustules,  which 
are  very  small  and  sensible  to  the  touch. 

The  different  species  of  herpes  all  arise  from  chronic  cu- 
taneous inflammation.  They  vary  in  form,  and  most  of 
them  appear  to  have  their  seat  in  the  superficial  or  epider- 
mic laminse  of  the  skin.  M.  Gendrin  is  of  opinion  that 
they  originate  in  the  sebaceous  follicles. — The  different 
kinds  of  tinea  appear  also  to  attack  at  first,  the  superficies 
of  the  skin,  and  to  be  propagated  by  degrees  to  the  thick- 


TEGUMENT ARY  SYSTEM.  205 

ness  of  this  membrane.  It  has  long  been  known  to  physi- 
cians that  the  tinea  favosa  has  its  seat  in  the  sebaceous 
follicles  and  the  bulbs  of  the  hair.  The  skin  is  susceptible 
of  undergoing  fibrous  and  cartilaginous  transformations; 
of  the  excessive  development  of  the  retiform  lamina,  giv- 
ing rise  to  certain  congenital  stains  (nsevi,)  which  are  of 
a  red  or  purple  colour,  and  of  an  alteration  of  the  pigmen- 
tum  nigrum.  In  those  persons  termed  Albinoes  the  pig- 
ment is  entirely  wanting,  in  consequence  of  which  the 
skin  presents  a  whiter  appearance  than  naturally,  with  a 
slight  shade  of  red,  owing  to  the  presence  of  blood. 


section  3. 

Of  the  Mucous  Membranes. 

Synonyma:  Glandulous  membranes,  internal  membrane  of  the  intestinal 
canal,  of  the  nasal  fossae,  Sec,  pituitary  membrane  of  the  nasal  fossae, 
villous  membrane,  villoso-papillary  membrane,  &c,  in  the  digestive 
apparatus. 

Definition. — Under  the  generic  name  of  mucous  mem- 
branes are  comprehended  all  those  parts  of  the  tegumentary 
system,  which  being  continuous  with  the  skin,  dip  into  the 
interior  parts  of  the  body  and  line  all  the  cavities  which 
communicate  with  the  exterior  world. 

Division. — The  internal  tegumentary  system  consists  of 
two  non-continuous  parts,  the  g astro-pulmonary  and  the 
genito -urinary. 

Situation  and  arrangement. — The  gastro-pulmonary 
mucous  membrane  lines  the  mouth,  where  it  is  continuous 
with  the  skin  of  the  lips,  and  successively  the  pharynx, 
the  oesophagus,  the  stomach  and  intestines  at  the  extremity 
of  which  it  is  again  continuous  with  the  skin:  during  this 
course  the  gastro-mucous  membrane  sends  different  pro- 
longations to  the  excretory  ducts  of  the  glands  which 
communicate  with  the  intestinal  canal.     In  the  fauces, 


206  TEGUMENTAHF  SYSTEM. 

the  gastro-pulmonary  membrane  sends  prolongations,  un- 
der the  name  of  the  pituitary  membrane,*  to  the  nasal 
fossas  and  their  sinuses,  presenting  an  exterior  communica- 
tion on  the  margin  of  the  nostrils  where  it  meets  the  skin, 
penetrating  superiorly  into  the  nasal  canal,  lining  a  part  of 
the  globe  of  the  eye  and  the  internal  surface  of  the  eye- 
lids, at  the  free  margins  of  which  it  gives  place  to  the  skin: 
in  the  posterior  part  of  the  mouth  it  enters  the  Eustachian 
tube,  lines  the  cavity  of  the  tympanum  and  the  mastoidean 
cells;  in  the  inferior  part  of  the  pharynx  it  dips  into  the 
larynx,  the  trachea,  the  bronchia  and  all  their  ramifica- 
tions. 

The  genito-urinary  mucous  membrane  of  the  male  sub- 
ject, begins  at  the  corona  of  the  glans  penis,  enters  the 
urethra,  lines  the  internal  surface  of  the  bladder,  the  ureters, 
the  infundibula,  and  even  the  calices  of  the  kidneys.  In 
the  female  it  commences  at  the  internal  surface  of  the  labia 
pudendi,  and,  after  having  lined  the  clitoris  and  the  vulva, 
it  sends  prolongations  into  the  urinary  passages,  which  it 
lines  in  the  same  manner  as  in  the  male,  invests  the  vagina, 
extending  as  far  as  the  cervix  uteri,  is  reflected  upon  its 
external  surface,  but  is  so  indistinct  in  the  cavity  of  this 
organ  that  its  existence  is  dubious.t 

•  Also  called  the  Sckneiderian  membrane,  in  honour  of  Professor 
Schneider,  a  German  anatomist,  Mho  published  about  the  middle  of  the 
seventh  century.     S.  D.  G. 

•j-  The  opinion  of  the  non  existence  of  the  mucous  membrane  in  the 
cavity  of  the  uterus,  entertained  by  some  anatomists,  has  no  doubt  arisen 
from  the  fact  that  this  membrane,  in  lining'  the  uterus,  becomes  exceed- 
ingly soft,  delicate  and  vascular.  At  the  cervix  uteri  it  is  tucked  up  in 
the  form  of  transverse  rugse,  which  have  sometimes  been  described  as 
being  disposed  in  a  foliated  direction,  and,  in  the  cavity  of  the  womb, 
there  are  a  few  smaller  rugre,  arranged  longitudinally,  in  respect  to  the 
body  of  the  uterus.  Between  these  rugs  there  are  several  follicles 
which  secrete  a  mucous  fluid.  From  the  cavity  of  the  womb,  the  mu- 
cous membrane  extends  to  the  fallopian  tubes,  invests  them  completely, 


TEGUMENTARY  SYSTEM.  207 

Conformation. — The  form  of  the  mucous  membranes, 
like  that  of  the  whole  system  to  which  they  belong,  results 
from  the  conformation  of  the  parts  which  they  cover. 
Nevertheless,  this  form  is  modified  by  the  numerous  folds 
which  are  presented  by  this  membrane  in  several  parts  of 
its  extent.  The  largest  of  these  folds  form  true  valves, 
composed  of  two  laminae,  contiguous  at  their  adherent  sur- 
face, and  containing  between  them  cellular  tissue,  blood- 
vessels, and  muscular  fibres,  as  in  the  velum  pendulum 
palati  and  the  ilio-ccecal  valve.  Many  of  these  duplicatures 
occur  on  the  internal  surface  of  the  small  intestines,  but 
they  are  much  smaller  than  the  preceding,  and  are  known 
under  the  name  of  valvulse  conniventes.  Finally,  these 
duplicatures  occur  on  the  internal  teguments  in  the  form 
of  simple  rugse,  which  add  to  the  size  of  the  organ  which 
they  cover:  in  the  stomach  they  are  distinguished  by  their 
volume;  in  the  vagina,  by  their  regularity. 

Surfaces. — The  mucous  membrane  presents  two  sur- 
faces, one  of  which  is  free,  the  other  adherent;  the  first 
presents  small  inequalities,  formed,  some  by  the  small  pa- 
pillary eminences  and  villi,  others  by  the  small  depres- 
sions which  constitute  the  mucous  and  phaneric  follicles. 

The  papillae  are  small  conical  eminences,  which  are  con- 
spicuous only  in  some  parts  of  the  mucous  membranes, 
and  particularly  on  the  superior  surface  of  the  tongue,  on 
the  corona  of  the  glans  penis,  and  the  clitoris;  they  are 
formed  of  all  the  laminae  of  the  mucous  membranes.  The 
villi  belong  probably  exclusively  to  the  gastro-intestinal 
membrane,  and  are  particularly  conspicuous  in  the  stomach, 
the  duodenum,  and  the  jejunum.  They  consist  of  small 
foliaceous  eminences,  varying  in  form,  and  being  generally 
larger  at  their  free  extremity  than  at  their  point  of  inser- 
tion, and  formed  by  the  entire  thickness  of  the  membrane, 
on  the  surface  of  which  they  unite  and  present  a  velvety  ap- 

and  projects,  according1  to  some  anatomists,  beyond  their  broad  extre- 
mities so  as  to  form  their  fimbriated  processes.     S.  D.  G. 


20S  TEGUMENTAL  SYSTEM. 

pearancc.  These  small  prolongations  are  short  and  large 
in  the  stomach  and  duodenum;  long  and  narrow  in  the 
jejunum  and  the  commencement  of  the  ilion:  they  are  dis- 
posed in  nearly  parallel  lines.  Some  anatomists  are  of 
opinion,  that  the  free  extremities  of  the  villi  are  provided 
with  small  orifices,  which,  according  to  them,  are  the  open 
mouths  of  the  capillary  vessels.  The  follicular  depressions, 
which  are  ohserved  on  the  free  surface  of  the  mucous  mem- 
branes, consist  either  of  simple  porous  orifices  or  of  small 
lacunae;  but,  besides  these  follicles,  there  are  others,  which, 
though  unimportant  in  the  human  subject  and  only  observ- 
able in  his  alimentary  canal,  with  the  aid  of  the  microscope, 
are  very  well  developed  in  the  second  stomach  of  rumina- 
ting animals,  where  they  constitute  the  large  cells  and  al- 
veoli of  the  mucous  membrane. 

The  adherent  surface  of  the  mucous  membranes  presents 
numerous  small  eminences,  which  are  formed  by  their  folli- 
cular depressions,  and  is  firmly  united  with  the  sub-mucous 
layer  of  the  cellular  tissue,  to  which  we  alluded  in  the 
first  chapter.  This  layer,  which  forms  one  of  the  tunics 
of  the  hollow  organs,  and  which  has  been  improperly 
termed  the  nervous  coat,  gives  attachment  to  the  fibres  of 
their  muscular  tunics,  adheres  sometimes  to  the  periosteum 
or  the  perichondrium,  and  in  some  instances,  as  in  the 
aerial  passages,  to  the  fibrous  or  fibro-cartilaginous  organs. 
In  these  cases,  the  adhesion  is  generally  so  intimate  that  it 
is  often  impossible  to  separate  the  mucous  membranes  from 
the  subjacent  parts:  hence,  the  name  of  the  fibro-mucous 
membranes.  The  adherent  surface  of  the  mucous  mem- 
branes is  in  relation  with  a  great  number  of  vessels  and 
nerves,  and,  we  have  already  seen,  that  in  the  duplicatures 
which  they  form,  the  external  surface  is  contiguous  to  it- 
self, and  has  interposed  between  its  two  laminae,  a  layer  of 
cellular  substance,  and  sometimes  a  plane  of  muscular 
fibres. 

Structure. — There  are  not  only  great  differences  in  the 


TEGUMENTARY  SYSTEM.  209 

organization  of  the  external  and  of  the  internal  teguments, 
but  also  in  the  different  parts  of  the  latter.  Thus,  the  mu- 
cous membranes  do  not  by  any  means,  and  in  a  very  evi- 
i  dent  manner,  present  all  the  laminse  which  enter  into  the 
composition  of  the  skin;  and  besides,  the  number  of  lami- 
nse which  it  is  possible  to  distinguish  in  them,  is  not  the  same 
in  the  different  parts  of  these  membranes,  nor  are  their 
anatomical  characters  everywhere  alike.  In  regard  to  their 
organization,  it  is  to  be  observed,  that  the  mucous  mem- 
branes do  not  present  a  distinct  retiform  body,  and  that  we 
can  distinguish  in  their  composition  only  two  layers,  the 
chorion  and  the  epidermis.  Under  the  second  point  of 
view  we  may  observe,  that  the  epidermic  layer,  which  is 
here  known  under  the  name  of  epithelium,  is  only  appre- 
ciable in  certain  parts  of  the  mucous  membranes,  viz.  from 
the  mouth  to  the  cardaic  orifice  of  the  stomach,  from  the 
vulva  to  the  cervix  uteri,  and  generally,  to  a  certain  ex- 
tent, in  those  parts  where  the  mucous  membranes  are  con- 
tinuous with  the  skin.  As  to  the  differences  which  exist 
between  the  two  laminse  composing  the  internal  tegu- 
ments, and  the  layers  which  correspond  to  those  of  the 
skin,  the  following  description  will  suffice  to  give  an  idea. 
The  chorion,  or  mucous  dermis,  alone  constitutes  the 
mucous  membranes  of  the  mastoidean  and  frontal  sinuses, 
the  conjunctiva  of  the  eye,  of  all  the  excretory  ducts,  of 
the  stomach  and  intestinal  canal,  and  of  the  whole  uri- 
nary apparatus,  except  in  the  neighbourhood  of  the  ex- 
ternal orifice  of  the  urethra.  The  chorion  is  presented 
under  the  appearance  of  a  soft,  spongy  substance,  appa- 
rently destitute  of  texture,  except  in  the  neighbourhood 
of  the  skin;  the  layer  which  it  forms  is  generally  much 
thinner  and  denser  in  proportion  as  it  recedes  from  the 
skin,  being  remarkably  tenuous  and  delicate  in  the  pro- 
longations which  line  the  excretory  ducts.  The  mucous 
dermis  is  extremely  vascular,  and  its  vascularity  is  in  di- 
rect ratio  with  the  number  of  the  different  follicles,  the 
28 


210  TEGUMENT ARY    SYSTEM. 

papillae  and  villi  which  it  presents  in  the  different  organs. 
As  to  the  nerves  of  this  layer,  they  can  only  be  traced  to 
certain  parts  of  its  extent,  as  to  the  papillae,  the  pituitary 
membrane,  &c.  The  papillae  of  the  mucous  dermis  are  « 
formed  of  the  capillary  vessels  and  nerves  which  are  upon 
its  surface,  and  are  defended  by  cellular  tissue:  the  dispo- 
sition of  the  capillary  veins  of  these  small  eminences  is 
such  as  to  render  them  erectile,  a  property  which  is  very 
conspicuous  in  the  papillae  of  the  tongue  during  degusta- 
tion.*  The  villi  are  composed  of  lymphatic  and  sanguine- 
ous capillaries,  which  project  upon  the  free  surface  of  the 
mucous  dermis,  and  are  accompanied  and  protected,  like 
the  papillae,  by  cellular  substance. 

The  epidermis  of  the  mucous  membranes  is,  as  we  have 
already  said,  found  only  in  certain  parts  of  the  internal 
tegumentary  system.  Wherever  it  does  not  exist,  and  par- 
ticularly upon  the  villi  of  the  intestines,  there  is  a  layer  of 
diffluent  substance  which  covers  the  chorion,  and  appears 
to  fulfil  the  office  of  the  epidermis,  which  itself  is  perhaps 
nothing  more  than  this  substance  in  a  state  of  desiccation. 
In  other  respects,  the  epidermis,  which  is  more  thick  where 
it  covers  the  papillae,  and  especially  upon  the  tongue,  than 
anywhere  else,  becomes  gradually  more  and  more  thin  and 
delicate  as  it  recedes  from  the  skin. 

The  mucous  follicles  or  glandulas  mucipersn  are  form- 
ed, like  those  of  the  skin,  by  the  depression  of  the  inter- 
nal tegument:  they  consist  of  very  small  cysts  with  a  nar- 
row neck,  and  open  upon  the  free  surface  of  the  mucous 
membrane  by  a  funnel-like  orifice.  They  are  generally 
found  in  every  part  of  the  mucous  system;  but  on  account 
of  their  volume  they  can  not  be  every  where  readily  per- 
ceived: they  occur  either  separately  or  in  clusters,  and 

*  Between  the  dermis  and  the  epidermis  of  the  lingual  papillae,  there 
is  a  kind  of  diffluent  substance,  which  is  probably  analogous  to  the  rete 
mucosum  of  Malpighi.     It  is  destitute  of  the  pigmentum  nigrum. 


TEGUMENTARY  SYSTEM.  211 

where  this  is  the  case,  they  open  separately  upon  the  sur- 
face of  the  mucous  membrane,  or  they  terminate  in  one  or 
more  small  cavities,  which  are  commonly  called  lacunas, 
and  which  perform  the  office  of  excretory  ducts:  the  amyg- 
dalae are  nothing  but  a  mere  cluster  of  follicles,  and  the 
same  obtains,  with  regard  to  the  glands  of  Cowper,  the  pros- 
tate, and  the  caruncula  lacrymalis.  In  the  fossa  navicu- 
lars of  the  urethra,  the  base  of  the  tongue,  &c,  they  are 
smaller  and  less  numerous,  and  the  lacunas  upon  which 
they  border  are  sufficiently  well  developed.  The  mucous 
follicles  receive  numerous  blood-vessels  and  nerves,  and 
wherever  the  epidermis  exists,  it  penetrates  into  their  ex- 
cretory ducts. 

Characters,  physical  and  chemical  properties. — The 
colour  of  the  mucous  membranes  varies  from  a  beautiful  red 
to  a  faint  rose  or  grayish.  The  former  generally  occurs 
in  the  neighbourhood  of  the  skin,  particularly  on  the  lips, 
the  tongue,  the  fauces,  the  internal  surface  of  the  eye-lids, 
the  glans  penis,  the  vulva,  &c;  the  latter  is  found  in  the 
greatest  part  of  the  teguments  of  the  alimentary  canal  of 
the  genito-urinary  apparatus,  &c.  The  mucous  membranes 
which  are  in  relation  with  the  bile,  commonly  receive  a 
yellowish  tint,  which  is  more  conspicuous  after  death  than 
during  life,  on  account  of  the  greater  activity  of  the  imbi- 
bition of  the  fluids  in  the  dead  body.  The  thickness  and 
density  of  the  mucous  membranes  are  extremely  variable; 
they  are  generally  at  their  maximum  in  the  neighbour- 
hood of  the  skin,  (if  we  except  the  conjunctiva,  which  is 
exceedingly  delicate,)  and,  in  proportion  as  they  recede 
from  this,  they  become  gradually  thinner:  the  mucous  mem- 
branes of  the  minute  ramifications  of  the  bronchia,  of  most 
of  the  excretory  ducts  of  the  glands,  and  of  the  frontal  and 
maxillary  sinuses,  are  at  the  minimum  of  the  two  charac- 
ters to  which  we  have  just  alluded.  In  general,  the  inter- 
nal teguments  are  of  a  soft,  spongy  consistence,  have  but 
little  tenacity,  but  a  great    degree   of  hygrometricity, 


212  TEGUMENTARY  SVSTEM. 

They  are  essentially  gelatinous,  and  when  exposed  to  pu- 
trefaction, they  yield  readily  to  its  action.  By  the  con- 
centrated sulphuric  acid,  they  may  be  converted  into  a 
soft,  pulpy  mass;  while  the  nitric  acid  imparts  to  them  a 
yellowish  orange  colour  before  it  dissolves  them,  especial- 
ly to  those  of  the  lips,  of  the  pharynx  and  the  oesophagus. 
This  is  an  important  character  to  be  known,  because  it  con- 
stitutes one  of  the  signs  of  poisoning  by  this  fluid,  though  it 
produces  the  same  effects  in  the  other  organic  solids  of  the 
body. 

Vital  properties. — The  mucous  membranes  are  slightly 
contractile;  and  although  they  are  generally  sensible,  this 
property  is  obscure  in  the  greatest  part  of  their  extent;  it 
is  more  remarkable  in  the  neighbourhood  of  the  external 
teguments,  particularly  in  the  mucous  membranes  of  the 
mouth  and  nasal  fossae,  which  are  supplied  with  the  nerves 
of  taste  and  of  smell,  and  in  the  tegumentary  membranes 
of  the  glans  penis  and  of  the  vulva. 

Differences  according  to  age. — In  the  foetus,  the  mu- 
cous membranes  are  extremely  thin  and  soft,  and  their  pa- 
pillae are  indistinct;  their  adhesion  to  the  subjacent  parts  is 
readily  broken,  and  their  colour  is  rather  violaceous  than 
red.  The  mucous  membrane  of  the  intestinal  canal,  at  the 
same  time,  contains  a  brownish  matter,  which  resembles 
the  juice  of  the  poppy,  and  is  hence  called  meconium. 

After  birth,  the  internal  teguments  retain  for  a  long 
time,  their  softness  and  delicac)\  They  are  generally  of  a 
faint  reddish  colour,  which  is  more  distinct  in  infancy  and 
youth  than  at  any  other  period.  In  adult  age,  they  gradu- 
ally lose  their  reddish  appearance  and  become  grayish: 
in  old  age,  they  become  more  dense,  and  lose  their  vel- 
vety character. 

Functions. — The  mucous  membranes  are  organs  of  ab- 
sorption, a  function  which  they  enjoy  in  a  very  high  de- 
gree, in  consequence  of  the  softness  and  delicacy  of  the 
epidermis,  and  on  account  of  the  absence  of  this  lamina  in 


TEGUMENTARY  SYSTEM.  213 

the  greater  part  of  their  extent'.  In  the  digestive  canal, 
this  function  is  rendered  extremely  vigorous  by  the  pre- 
sence of  the  small  vascular  papillae. 

The  mucous  membranes  are  also  organs  of  serous  and 
mucous  secretions:  the  latter  of  which  belongs  chiefly  to 
the  mucous  follicles.  The  mucous  fluids  vary  in  the  dif- 
ferent parts  of  the  internal  tegument,  though  they  every 
where  contain  animal  mucus,  which  forms  their  basis.* 

Some  of  the  mucous  membranes  are  the  seat  of  particu- 
lar sensorial  impressions,  by  virtue  of  the  nerves  which 
they  receive;  thus,  the  sensation  of  hunger  is  referred  to 
the  mucous  membrane  of  the  stomach,  that  of  taste  to  the 
mucous  membrane  of  the  mouth,  and  especially  to  the  pa- 
pillae on  the  surface  of  the  tongue,  and  that  of  smell  to  the 
mucous  membrances  of  the  nasal  fossse.  There  is  also  a 
very  remarkable  connexion  between  the  mucous  membranes 
and  the  skin,  the  circulatory  centre,  the  nervous  system,  &c. 

Pathological  Jlnatomy. 

The  mucous  membranes  participate  in  the  congenital  or 
acquired  mal-conformations,  as  well  as  in  the  displacements 
of  the  organs  which  they  cover:  they  are  also  subject  to 
peculiar  deformities,  as  in  cases  of  hernia. 
.  When  a  mucous  canal  ceases  to  be  traversed  by  the  fluids 
to  which  it  gives  passage,  it  undergoes  a  more  or  less  con- 
siderable contraction:  on  the  contrary,  however,  when 
the  fluids  are  more  abundant  than  usual,  the  mucous  mem- 
brane becomes  much  dilated,  and  recovers  but  slowly  its 
primary  dimensions  after  the  cause  of  its  distention  has 
ceased  to  act. 

Inflammation  of  the  mucous  membranes  is  a  very  fre- 
quent and  often  a  very  troublesome  disease.  It  is  general- 
ly characterized  by  a  coloration  which  varies  from  a  rose 

*  It  is  impossible  to  give  a  correct  anafysis  of  these  fluids,  on  account 
of  their  being-  more  or  less  mixed  with  the  other  secretions,  such  as  the 
lacrymal  fluid,  the  saliva,  the  bile,  the  pancreatic  fluid  and  the  urine. 


214  TEGUMENTARY  SYSTEM. 

to  a  deep  brown,  and  is  presented  either  under  an  arbores- 
cent form,  or  under  that  of  small  red  points  disseminated 
over  a  pale  or  reddish  base,  (as  when  the  villi  alone  are  in- 
flamed,) or  again  under  that  of  regular  uniform  spots,  which 
are  most  frequently  of  a  red  colour,  sometimes  violaceous 
or  livid,  and  sometimes  again  argillaceous  or  brownish.* 
Besides  its  change  of  colour,  the  mucous  membrane  aug- 
ments in  thickness  at  the  same  time  that  it  loses  its  re- 
sistance, becomes  more  soft,  and  is  easily  detached  from 
the  subjacent  tissues.  Its  secretion,  which  is  more  active 
at  the  beginning  of  the  inflammatory  stage,  furnishes  a  kind 
of  viscid  fluid,  which  is  more  or  less  puriform,  but  often 
only  more  abundant  or  serous  than  natural;  when,  however, 
the  inflammation  has  attained  its  height  of  intensity,  the 
mucous  secretion  is  completely  suspended  until  it  begins 
to  decline:  the  secretion  now  becomes  often  puriform,  and 
even  purulent,  without  there  being  any  ulceration  of  the 
part  affected;  at  other  times,  however,  the  inflamed  mucous 
membranes  secrete  a  substance  which  is  deposited  and  in- 
spissated upon  their  free  surface,  under  the  form  of  false 
membranes. — The  presence  of  similar  productions  in  the 
larynx  characterizes  the  species  of  laryngitis  known  under 
the  name  of  croup.  Pseudo-membranes  are  also  formed 
in  certain  cases  of  angina  pharyngea  and  trachialis,  in  some 
of  the  phlegmasise  of  the  mucous  membranes  of  the  bron- 
chia and  intestinal  canal,  and  sometimes,  though  extremely 
seldom,  in  the  other  mucous  membranes.  These  produc- 
tions are  susceptible  of  becoming  organized  like  those  of 
the  serous  membranes,  yet  this  is  of  rare  occurrence,  be- 
cause they  are  ordinarily  thrown  off  by  the  efforts  of  vo- 
miting, by  stool,  &c,  or  because  the  subject  succumbs  in  the 
incipient  stage  of  the  organization;  at  other  times,  the  in- 
flammation diminishes,   and  the  internal  tegument  again 

*  The  arborescent  inflammatory  coloration  is  the  only  one  which 
yields  to  washing  and  maceration;  all  the  others  do  not  undergo  the  least 
diminution  of  intensity. 


TEGU.MENTARY    SYSTEM.  215 

secretes  a  fluid,  which  raises  the  false  membrane  and  de- 
taches it  completely;  or  the  secretion  not  taking  place,  the 
morbid  production  gradually  diminishes,  becomes  semi- 
transparent,  and  finally  entirely  disappears.  The  acute 
inflammations  of  the  mucous  membranes  sometimes  termi- 
nate in  ulceration:  in  this  case  their  edges  are  somewhat 
jutting,  extremely  red,  and  covered,  like  their  base,  with 
a  mucous  puriform  substance.  These  phlegmasia  also 
sometimes  terminate  in  gangrene,  either  by  reason  of  their 
violence,  or  because  of  their  essentially  phagedenic  cha- 
racter, as  is  the  case  in  the  anginose  gangrenous  epide- 
mics; the  development  of  small  vesicles  upon  the  affected 
part  often  indicates  this  termination.  The  eschars  of  the 
mucous  membranes  vary  from  a  grayish  to  a  blackish- 
brown  colour,  and  commonly  present  the  appearance  of  a 
putrid  deliquescence. 

In  many  subjects  who  die  with  croup  there  are  symp- 
toms of  mucous  fever,  an  inflammation  of  the  cryptse  of 
the  internal  gastro-intestinal  tegument,  which  produces 
genuine  pustules,  of  a  grayish  or  whitish  colour,  and  filled 
with  a  mucoso-purulent  fluid;  in  the  centre  of  these  pus- 
tules we  observe  a  small  depression  or  black  point,  which 
indicates  the  orifice  of  the  crypta.  This  affection  has  been 
chiefly  described  by  Rcederer  and  Valger.  M.  Bretonneau, 
of  Tours,  however,  has  paid  much  attention  to  the  pustu- 
lous inflammation  of  the  follicles  of  the  mucous  membrane 
of  the  intestines,  and  has  given  it  the  name  of  dothinente- 
ritis, — a  disease  which  readily  assumes  a  chronic  cha- 
racter, and  often  terminates  in  ulceration  of  the  affected 
cryptse.  In  small-pox  the  mucous  membranes  are  some- 
times affected  with  pustulous  inflammations:  in  these  cases, 
the  pustules,  ordinarily  superficial,  though  sometimes 
situated  in  the  thickness  of  the  chorion,  are  not  constantly 
depressed,  nor  do  they  appear  to  have  the  areolar  disposi- 
tion of  those  of  the  external  tegument. 

The  chronic  phlegmasiae  of  the  mucous  membranes  are 


216  TKGUMENTAKY    SYSTEM:. 

generally  characterized  by  a  bright  red,-livid  or  copper-co- 
lour, and  by  a  thickening  and  hardening  of  the  affected 
parts,  whose  tissue  is  of  a  more  homogeneous  nature  than 
in  the  normal  state. — The  growths,  which  are  sometimes 
observed  on  the  surface  of  the  mucous  membranes,  result 
from  a  morbid  development  of  their  capillaries,  occasioned 
by  a  protracted  irritation  or  chronic  inflammation.  The 
ulcerations,  which  are  produced  by  chronic  inflammation, 
are  characterized  by  hard,  elevated,  jaggy  edges,  while  the 
base  of  the  ulcer  is  rugose,  and  of  a  red,  livid  or  copper-co- 
lour: this  morbid  state  is  generally  accompanied  by  the  se- 
cretion of  puriform  or  purulent  matter,  even  where  there  is 
no  ulceration.  Polypi  of  the  mucous  membranes  and  the 
erectile  productions,  which  are  sometimes  accidentally  de- 
veloped in  their  thickness,  as  well  as  the  cartilaginous  and 
osseous  metamorphoses,  may  also  be  referred  to  protracted 
irritation  or  chronic  inflammation.  The  mucous  mem- 
branes are  often  the  seat  of  sanguineous  congestions,  which 
may  be  either  active  or  passive,  accordingly  as  they  are  oc- 
casioned by  the  irritation  of  their  tissue,  or  by  an  obstruc- 
tion in  the  circulation. 

In  these  cases  the  thickness,  density,  and  consistence  of 
the  membrane  are  in  no  wise  altered,  nor  is  there  any  mor- 
bid secretion  upon  its  surface.  These  congestions  may 
bring  on  hemorrhage  and  even  inflammation.  The  mu- 
cous membranes  are  sometimes,  though  rarely,  the  seat  of 
pilous  and  corneous  productions;  when  these  are  exposed 
for  a  certain  time  to  the  atmosphere  they  assume  the  cha- 
racters of  the  external  teguments.  The  membranes  which 
line  fistulous  openings,  certain  cysts,  and  most  of  the  puru- 
lent abscesses,  may  be  referred  to  the  order  of  mucous 
membranes. 


TEGUMENT ARY  SYSTEM.  217 

SECTION  4. 

Of  the  Appendages  of  the  Tegumentary  System. 

The  appendages  of  the  tegumentary  s)7stem  are  the  solid 
parts  which  are  produced  by  the  bulbous  or  phaneric  folli- 
cles, and  project  upon  the  free  surface  of  the  teguments. 
These  parts  are: — the  hairs  and  the  nails  for  the  external 
tegument,  and  the  teeth  for  the  internal. — Before  we  enter 
upon  the  particular  history  of  each  of  these  products,  we 
shall  endeavour  to  give  a  general  idea  of  the  generative 
part — the  bulb. 

The  bulb  is  a  small  vesicle,  which  is  situated  in  the 
thickness  of  the  dermis,  opens  upon  its  free  surface,  and 
is  continuous  by  the  margins  of  its  orifice  with  the 
tegumentary  membrane,  of  which  it  is  really  a  mere  de- 
pression: in  fact,  the  small  organ  of  which  we  are  speak- 
ing is  composed,  1st,  of  a  lamina  which  is  analogous  to 
the  dermis,  and  which,  being  in  relation  with  the  sub- 
cutaneous cellular  tissue,  gives  passage  to  blood-vessels 
and  nerves  which  ramify  principally  upon  its  concave 
surface;  2d,  of  a  pulpy  substance  which  is  formed,  as  it 
were,  of  the  termination  of  the  blood  vessels  and  nerves  of 
the  chorion,  and  represents  the  retemucosumof  Malpighi; 
3d,  and  lastly,  of  the  dead  inorganic  product,  which  is 
analogous  in  this  respect,  and  sometimes  also  in  its  chemi- 
cal composition,  to  the  epidermis. 


article  1. 

Of  the  Hairs. 

Definition. — The  hairs  are  the  filamentous  inorganic 
parts,  which  project  upon  the  free  surface  of  the  external 
tegument,  and  are  of  variable  length,  fineness  and  delicacy. 
29 


218  TEGUMENTAUY  SYSTEM. 

Division  and  situation. — The  hair  is  distinguished  by 
different  names  according  to  the  part  where  it  is  situated, 
as  capillus,  on  the  scalp;  supercilium,  on  the  eye-brows; 
cilium,  on  the  eye-lids;  circi'inus,  on  the  temples;  barba, 
on  the  chin,  and  mystax,  on  the  upper  lip.  The  generic 
name  of  hair,  moreover,  is  applicable  to  all  the  pilous  pro- 
ductions which  occur  upon  the  surface  of  the  trunk,  and 
the  extremities.  There  are  no  hairs  in  the  palm  of  the 
hand  and  the  sole  of  the  foot;  and  they  are  extremely  thin 
and  delicate  in  some  parts  of  the  face,  the  internal  parts  of 
the  extremities,  and  on  the  back:  they  generally  occur  in 
considerable  abundance  on  the  sternal  parts  of  the  thorax, 
and  the  external  parts  of  the  extremities,  particularly  in 
the  male. 

Form. — The  generative  part,  or  pilous  bulb,  represents 
a  small  ovoid  vase,  which  is  open  on  the  free  surface  of  the 
teguments.  The  hair,  properly  so  called,  is  of  a  conical 
form,  being  more  delicate  at  its  free  than  at  its  bulbous  ex- 
tremity.    It  is  either  straight,  twisted,  or  curled. 

Structure. — The  bulb  of  the  hair  is  really  nothing  but  a 
small  oblique  depression  of  the  skin,  and  consists  of  the 
same  number  of  lamina?.  The  pigment  itself  exists  in  the 
part  which  represents  the  rete  mucosum.  The  greater  part 
of  the  bulb  is  filled  by  a  cone  of  pulpy  substance;  and  upon 
this  papilliform  body  is  implanted  the  inorganic  part,  or 
the  hair  properly  so  called.  At  its  adherent  part,  the  pilous 
follicle  has  capillary  vessels  and  nerves  which  stimulate  its 
small  roots. 

The  hair  itself  embraces,  by  its  hollow  and  diffluent  base, 
the  pulpous  cone  of  the  bulb;  and  the  surrounding  epider- 
mis, after  having  invested  the  orifice  of  the  bulb,  is  reflect- 
ed upon  the  base,  and  is  confounded  with  the  hair.* — The 

*  This  double  mode  of  union  of  the  hairs  with  the  skin,  renders  the  ad- 
hesion of  these  two  organs  so  intimate,  that  it  can  not  be  broken  without 
a  certain  degree  of  difficulty  and  of  pain.     All  such  efforts  as  have  a  ten- 


TEGUMENT ARY   SYSTEM.  219 

hair  is  a  white  epidermic  sheath,  containing  a  colouring 
matter  which  is  disposed  in  numerous  filaments,  between 
which  there  is  a  liquid  substance  for  the  purpose  of  con- 
necting them  with  each  other,  and  with  the  sheath.  This 
interior  coloured  part  represents  the  rete  mucosum  of  the 
skin,  and  upon  it  depends  the  colour  of  the  hair. — Neither 
blood  vessels  nor  nerves  can  be  traced  into  the  substance 
of  the  hair  itself,  the  bulb  being  the  only  part  which  re- 
ceives them. 

Characters,  physical  and  chemical  properties. — The 
colour  of  the  hair  varies  in  different  individuals  from  white 
to  jet  black,  passing  through  a  number  of  intermediate 
shades  of  pale  yellow,  reddish,  auburn,  &c:  it  is  never  of 
a  blue,  green,  or  yellow  colour,  &c.  In  the  Albinoes  the 
hairs  are  of  a  white  appearance.  Their  colour  is  generally 
the  same  in  the  different  parts  of  the  surface  of  the  body; 
yet  there  are  many  exceptions  to  this  rule.  The  thickness 
or  diameter  of  the  hairs  is  very  different  in  the  different 
parts  of  the  same  individual;  thus,  the  hairs  of  the  pubes 
are  the  thickest;  and  in  regular  succession  those  of  the  ax- 
illaa,  the  head,  the  eye-brows,  the  eye-lids,  the  beard,  &c. 
The  medium  of  this  diameter  is  about  the  six  hundredth 
part  of  an  inch.  Fair  hair  is  generally  the  most  fine  and 
delicate;  black,  the  most  rough.  The  hairs  greatly  resist 
such  causes  as  have  a  tendency  to  rupture  them  transverse- 
ly, but  they  are  easily  divided  in  a  longitudinal  direction. 
They  are  dry  and  solid  externally,  fluid  at  their  adherent 
extremity,  and  soft  within:  they  evidently  absorb  humidi- 
ty, and  enlarge.* 

The  hairs  resist  for  a  great  number  of  years  the  action  of 
putrefaction.  By  long  continued  boiling  in  Papin's  diges- 
ter, they  are  gradually  dissolved,  and  are  finally  converted 

dency  to  detach  the  epidermis  from  the  subjacent  laminae,  have  the  same 
effect  with  respect  to  the  hair  of  the  scalp. 

*  It  is  to  a  knowledge  of  this  fact  that  we  are  indebted  to  the  hy- 
grometer of  M.  De  Chaussier. 


220  TEOUMENTAUY  SYSTEM. 

into  mucus,  after  having  disengaged  a  quantity  of  hydro- 
sulphuric  acid  gas.  According  to  the  analyses  of  Vauque- 
lin,  black  hair  contains  a  large  proportion  of  an  animal  sub- 
stance, similar  in  all  respects  to  mucus,  a  white  inspissated 
oil,  a  small  quantity  of  thick  oil  of  a  greenish  black  colour, 
traces  of  the  oxides  of  manganese  and  iron,  of  silica,  sul- 
phur, phosphate  and  carbonate  of  lime,  and  sulphate  of 
iron.  According  to  this  chemist,  the  colour  of  the  hair  de- 
pends upon  the  presence  of  the  greenish  oil,  and  the  sul- 
phate of  iron.  This  oily  matter  is  either  of  a  greenish 
black  colour,  red,  yellow,  or  nearly  colourless,  according 
as  the  hair  is  black,  red,  yellow,  or  white. 

Vital  properties. — The  bulbs  of  the  hair,  and  particu- 
larly the  pulpy  portions,  are  the  only  parts  which  enjoy 
any  evident  sensibility;  the  hair  itself  being  completely 
destitute  of  vitality.  The  motions  which  are  sometimes 
observed  in  the  hairs  depend  upon  the  contractions  of  the 
cutaneous  tissue. 

Differences  in  the  different  races  of  men. — The  varie- 
ties of  colour  which  we  have  just  pointed  out  belong  al- 
most exclusively  to  the  individuals  of  the  Caucasian  race; 
and  amongst  them  we  may  observe  that  those  who  inhabit 
the  northern  countries,  have  generally  a  fairer  and  lighter 
pilous  system,  than  those  of  the  southern  regions.  In  all 
the  other  races  the  hair  is  black.  In  the  Caucasian  and 
Malay,  the  hair  is  generally  long,  fine,  thick,  and  often 
curled;  it  is  fine  and  thin  in  the  American,  short  and  coarse 
in  the  Mongolian,  crisped  and  woolly  in  the  Ethiopian. 

Differences  according  to  age  and  sex. — At  about  half 
the  term  of  pregnancy,  the  skin  of  the  foetus  is  covered 
with  an  external  soft  and  delicate  down,  which  falls  off 
sometime  after  birth,  and  of  which  traces  may  be  found  in 
the  liquor  amnii.  The  hair  of  the  head,  the  eye-lids,  and 
eye-brows,  appear  in  the  latter  months  of  gestation,  and 
are  the  first  amongst  the  permanent  pilous  parts  which  are 
developed.     The  other  hairs  do  not  appear  until  after  the 


TEGUMENT ARY  SYSTEM.  221 

age  of  puberty.  In  infancy  the  hair  is  generally  more  fine 
and  soft,  and  of  a  lighter  colour  than  in  adult  age.  In  the 
decline  of  life,  (and  sometimes  before)  the  hairs  become 
white  and  fall  off:  in  old  age  they  are  white  and  thin.  In 
the  female,  we  generally  observe  neither  beard,*  nor  whisk- 
ers, and  the  hair  upon  the  chest  and  the  external  parts  of 
the  extremities  are  very  thin  and  delicate. 

Functions. — The  pilous  bulb  secretes  the  substance 
which  forms  the  hair. — The  hair  is  an  organ  of  protection 
of  the  skin,  and  is  subservient  to  the  tactile  sensations  by 
the  facility  with  which  its  generative  pulp  receives  the  im- 
pressions from  such  bodies  as  touch  the  hair. 

Pathological  JLnatomy. 

When  the  hairs  are  plucked  out,  they  are  always  repro- 
duced, provided  the  bulb,  has  not  been  destroyed:  the  same 
thing  takes  place  in  the  diseases  of  the  bulb  which  occasion 
the  falling  off  of  the  hair,  The  bulb  is  sometimes  com- 
pletely altered  by  a  protracted  inflammation,  its  pilous  se- 
cretion ceases,  and  the  hairs  lose  their  colouring  matter. 
This  phenomenon,  as  we  have  already  said,  is  a  natural  con- 
sequence of  the  progress  of  age,  in  which  case  the  change 
of  colour  of  the  hair  takes  place  in  regular  progression;  but 
often,  and  chiefly,  in  consequence  of  moral  impressions, 
such  as  fear  and  grief,  they  become  suddenly  hoary  be- 
fore the  ordinary  period.  In  these  cases  they  sometimes, 
though  seldom,  recover  their  primary  colour.  We  are 
ignorant  in  the  present  state  of  our  knowledge,  of  the 
changes  which  supervene  in  the  follicles  of  the  hairs  after 
their  removal  or  discoloration.  In  the  disease  called 
plicaj  the  hairs  of  the  scalp  acquire  an   extraordinary 

*  There  are  some  individuals  of  the  female  sex,  however,  who  have  a 
sort  of  beard,  especially  on  the  upper  lip,  which  comes  on  either  about 
the  period  of  puberty,  or  after  the  cessation  of  the  menses. 

f  This  disease,  generally  termed  plica  polordca,  is  almost  peculiar  to 
the  inhabitants  of  Poland,  Lithuania,  and  Tartary. — S.  D.  G. 


222  TEGTTMENTAKY  SYSTEM. 

length,  and  become  entangled  in  a  very  intricate  manner: 
some  have  even  asserted  that  they  become  vascular  and 
sensible;  but  perhaps  there  is  nothing  real  in  this  opinion, 
which  at  least  has  been  exaggerated.  Beclard  has  endea- 
voured to  account  for  the  facts  upon  which  this  opinion 
rests,  (the  hemorrhage  and  pain  which  accompany  their 
cutting,)  by  supposing,  that  in  consequence  of  the  irritation 
which  the  bulb  experiences  in  the  disease  to  which  we 
have  alluded,  the  pulp  which  secretes  and  embraces  the 
hair  tumefies,  becomes  raised  above  the  level  of  the  tegu- 
ments, and  is  then  entangled  by  the  instrument  with  which 
the  affected  part  is  shaved. 

Hairs  are  sometimes  accidentally  developed  in  conse- 
quence of  inflammations  of  the  skin,  and  even  in  those 
parts  where  they  do  not  ordinarily  occur.  Numerous  cases 
have  been  related  in  which  hairs  are  said  to  have  been 
found  in  the  organs  which  are  lined  by  mucous  membranes; 
but  in  most  of  them  they  appeared  to  have  been  intro- 
duced. They  have  also  been  sometimes  found  in  certain 
cutaneous  cysts,  and  in  the  ovarium,  in  cases  of  extra-uterine 
pregnancy :  in  these  instances  the  hair  is  extremely  delicate, 
and  of  a  whitish  appearance.  The  hairs,  which  some  au- 
thors, such  as  Bonet,  and  Amatus  Lusitanus,  are  said  to 
have  found  upon  the  heart,  were  probably  nothing  but 
mere  pseudo-membranous  filaments. 


ARTICLE  2. 

Of  the  Nails. 

Definition. — The  nails  are  the  hard,  transparent  lamellae, 
which  cover  the  dorsal  parts  of  the  last  phalanges  of  the 
fingers  and  the  toes. 

Form  and  disposition. — The  nails  are  oblong,  and 
curved  in  such  a  manner  as  to  be  moulded  upon  the  parts 
which  they  cover.     They  are  divided  into  a  root,  body, 


TEGUMENTARY  SYSTEM,  223 

and  free  extremity.  The  root  is  posteriorly  and  is  placed 
within  a  duplicative  of  the  skin;  it  is  the  most  soft  and 
delicate  part  of  the  nail.  The  body  is  continuous  with  the 
root,  which  it  exceeds  in  thickness;  it  presentsposteriorly 
a  white  semi-lunar  part  with  the  convexity  before,  which 
is  called  the  crescent;  in  the  rest  of  its  exent,  the  body  of 
the  nail  is  of  a  faint  red  colour,  and  its  transparency  is  such 
as  to  permit  the  colour  of  the  subjacent  cutaneous  tissue  to  be 
seen.  The  anterior  or  free  extremity,  which  is  more  thick 
than  the  preceding  portion,  projects  more  or  less  beyond 
the  dorsal  part  of  the  finger.  When  nothing  prevents  its 
growth,  the  free  extremity  becomes  long  and  crooked  and 
acquires  an  increase  of  thickness.  The  nails  present  two 
surfaces,  one  of  which  is  convex,  the  other  concave;  both 
are  adherent  at  the  posterior  part,  and  free  at  their  anteri- 
or extremity;  at  the  middle  part,  the  concave  surface  is 
adherent,  but  the  convex  surface  is  free.  The  nails  adhere 
to  the  subjacent  cutaneous  laminae,  throughout  the  whole 
extent  of  their  circumference,  by  means  of  the  surrounding 
epidermis  which  serves  to  unite  them,  without,  however, 
its  being  confounded  with  them;  and,  besides,  their  root, 
which  is  lodged  within  a  kind  of  furrow  of  the  skin,  is 
there  intimately  connected  with  it.  Under  the  root  of  the 
nail,  the  dermis  is  of  a  whitish  appearance,  from  which  re- 
sults the  semi-lunar  spot  called  the  crescent;  under  the  mid- 
dle part,  on  the  contrary,  the  dermis  is  very  vascular,  and 
furnished  with  small  papillae. 

Structure. — The  nails  have  been  regarded  by  some 
anatomists,  particularly  by  Bichat  and  J.  F.  Meckel,  as 
being  formed  of  a  substratum  of  epidermic  laminae,  whose 
extent  diminishes  successively  from  behind  forwards,  in 
such  a  manner,  that  the  most  exterior  layer  forms  the 
length  of  the  nail,  and  the  most  internal  its  shortest  part. 
This,  in  fact,  appears  to  be  the  only  true  explanation  of  the 
differences  in  the  thickness  of  the  nails  in  the  different 
parts  of  their  extent.     According  to  others,  however,  such 


224  TEGUMENTAItY  SYSTEM. 

as  Blancardi  and  M.  de  Blainville,  the  nails  are  pilous  pro- 
ductions, which  are  agglutinated  together,  and  are  derived 
from  bulbs  similar  to  those  which  we  have  described  in  the 
preceding  article.  Indeed,  the  longitudinal  striae  which  are 
observed  upon  the  two  surfaces  of  the  nails,  would  appear 
to  indicate  an  analogy  between  them  and  certain  corneous 
productions,  which  very  evidently  result  from  the  aggluti- 
nation of  a  great  number  of  hairs.*  Notwithstanding, 
however,  the  plausibility  of  these  opinions,  we  are  una- 
ble to  decide  whether  the  nails  are  merely  a  thick  corne- 
ous epidermic  layer,  or  whether  they  are  secreted  by  pi- 
lous bulbs. 

Characters,  physical  and  chemical  properties.- — The 
nails  are  whitish, t  semi-transparent,  hard,  flexible  and 
elastic,  and,  like  the  epidermis,  they  are  principally  com- 
posed of  concrete  albumen. 

Vital  properties. — The  nails  are  destitute  of  vitality.  % 

Differences  according  to  age. — The  nails  are  brought 
into  existence  about  the  fifth  month  of  foetal  life.  Their 
thickness  and  consistency,  at  first  inconsiderable,  gradual- 
ly increase,  so  that  in  old  age  they  become  very  hard  and 
firm.  At  birth,  the  nails  do  not  always  reach  the  extre- 
mity of  the  finger,  and  seldom  jut  beyond  it. 

Functions. — In  man,  the  nails  serve  merely  to  defend 
the  free  extremities  of  the  fingers:  the  habit  of  paring 
them,  common  to  most  people,  renders  them  unfit  for  la- 
ceration. 

*  According  to  some  anatomists,  these  stria:  are  owing  to  the  linear 
disposition  of  the  papilla;  of  the  dermis. 

f  In  the  coloured  races,  the  pigmentum  nigrum  is  situated  in  the  sub- 
jacent parts,  and  the  blackish  appearance  of  the  nails  is  entirely  owing 
to  their  transparency. 

+  The  fact  that  so  much  pain  is  felt  when  the  nails  grow  into  the  flesh, 
and  that  the  operation  of  tearing  them  out  is  so  extremely  painful,  is  no 
doubt  owing  to  the  lesion  of  the  surrounding  parts. — S.  D.  G. 


TEGUMENTARY  SYSTEM.  225 

Pathological  Jinatomy. 

When  a  nail  has  been  torn  out,  or  has  been  detached  in 
consequence  of  a  disease  of  the  subjacent  dermis,  it  is  re- 
placed by  another,  which  bears  more  or  less  resemblance 
to  the  first,  accordingly  as  the  generative  part  is  healthy  or 
altered;  in  the  latter  case,  it  may  even  happen  that  there 
will  be  no  reproduction  at  all.  The  nails  are  often  sub- 
ject to  excrescences,  or  a  preternatural  thickening.  In  scro- 
fulous subjects,  or  those  who  are  affected  with  chronic 
diseases,  such  as  phthisis,  &c,  they  often  become  more 
brittle,  thin  and  convex,  than  in  the  healthy  state.  When 
the  nails  grow  into  the  surrounding  tissues,  it  often  gives 
rise  to  a  very  painful  affection,  which  may  be  attended 
even  with  inflammation  of  the  skin  which  is  in  contact  with  • 
the  sharp  edge  of  the  nail.  This  affection  is  almost  exclu- 
sively confined  to  the  great  toe,  and  is  occasioned  by  the 
wearing  of  tight  shoes. 


ARTICLE    3. 

Of  the  Teeth. 

Definition.  — The  teeth  are  the  small,  hard,  calcareous'or- 
gans  which  are  fixed  in  the  alveoli  of  the  superior  and  in- 
ferior maxillse,  and  are  produced  by  the  follicles  which  are 
dependant  on  the  mucous  membrane  of  the  mouth. 

Division. — Each  tooth  consists  of  a  body  and  a  root,  or 
that  part  which  is  fixed  in  the  socket.  The  boundary  be- 
tween these  two  is  called  the  neck  of  the  tooth. 

Texture. — The  teeth  present  two  well  marked  and  dis- 
tinct parts,  one  of  which  is  organic,  the  other  inorganic. 

The  organic  part  consists:  1st,  of  a  membrane  which  co- 
vers the  root  of  the  tooth  and  is  continuous  with  the  mu- 
cous membrane  of  the  gums;  2d,  of  a  neuroso-vascular  pul- 
py substance  which  represents  the  form  of  the  tooth,  and  is 
30 


226  TEGUMENTARY    SYSTEM. 

surrounded  by  it  on  all  sides,  except  in  one  or  two  points 
where  it  communicates  with  the  preceding  membrane  by- 
blood-vessels  and  nerves. 

The  inorganic  part  is  exactly  moulded  upon  the  pulp, 
and  is  composed  of  two  substances;  one  of  which  consti- 
tutes almost  the  entire  tooth,  and  is  called  the  osseous  or 
ivory  substance;  it  is  disposed  in  laminae  and  has  neither 
cellular  tissue,  blood-vessels  nor  nerves,  nor  the  areolar  tex- 
ture of  the  bones.  The  other  substance  is  termed  the  ena- 
mel, and  forms  a  layer  which  covers  the  preceding;  it  is  of 
a  white,  milky,  brilliant,  semi-transparent  appearance, 
more  hard  than  the  ivory  part  of  the  tooth,  upon  which  it 
is  exactly  moulded,  and  becomes  thinner  as  it  approaches  the 
neck  of  the  tooth.  The  enamel  has  no  trace  of  organiza- 
%  tion;  it  is  disposed  in  undulating  fibres,  which  are  united 
with  each  other  in  a  very  exact  manner,  and  are  directed 
obliquely  in  respect  to  the  axis  of  the  tooth. 

We  see,  then,  that  on  account  of  their  organization,  the  teeth 
could  not  have  been  included  in  the  osseous  system.  Be- 
sides this  distinctive  character,  and  that  which  is  drawn 
from  the  peculiar  situation  of  the  body  of  the  teeth,  we 
shall  readily  distinguish,  in  the  remainder  of  this  section, 
all  the  other  differences  which  exist  between  the  dental 
apparatus  and  the  passive  organs  of  locomotion.  The  den- 
tal apparatus  is  naturally  placed  upon  the  same  line  with 
the  hairs,  since  it  consists,  like  them,  of  a  follicular  part,  a  • 
generative  pulp,  and  an  exterior  dead  part;  their  chemical 
composition  being  the  only  difference  which  exists  be- 
tween these  two  productions.  Comparative  anatomy 
throws  but  little  light  upon  this  subject,  except  by  show- 
ing that  the  beaks  of  birds  are  analogous  to  the  teeth  of 
mamiferous  animals. 

Characters,  physical  and  chemical  properties. — The 
teeth  are  of  a  white,  very  slightly  yellowish  appearance, 
especially  in  their  alveolar  part:  the  crown  is  more  or  less 
brilliant,  on  account  of  the  enamel  which  covers  it.     The 


TEGUMENTARY  SYSTEM.  227 

hardness  of  the  teeth  exceeds  that  of  the  hardest  and  most 
solid  bone  in  the  body,  (the  petrous  portion  of  the  tempo- 
ral bone,)  a  property  which  they  owe  to  their  containing  a 
greater  quantity  of  calcareous  matter. — According  to  the 
analysis  of  M.  Berzelius,  the  osseous  substance  of  the 
teeth  is  composed  of  phosphate  of  lime,  51.04,  fluate  of 
lime  2.00,  carbonate  of  lime,  11. 30,  phosphate  of  magnesia, 
1.16,  soda,  1.20,  and  a  trace  of  the  hydro-chlorate  of  soda, 
and,accordingtoMr.  Pepis,of  a  small  proportion  of  gelatine. 
According  to  the  first  named  chemist,  the  enamel  consists  of 
the  same  salts  as  the  osseous  part,  but  in  different  proportions : 
the  phosphate  of  lime,  amongst  others,  being  much  more 
abundant  in  the  latter  than  in  the  enamel,  which,  according 
to  Hatchett,  Fourcroy  and  Vauquelin,  is  composed  of  the 
phosphate  of  lime,  in  combination  with  a  very  small  quan- 
tity of  gelatine. 

Development,  and  differences  according  to  age.  — The 
changes  which  the  dental  apparatus  experiences  during 
the  course  of  life  are  very  remarkable  and  curious.  Under 
this  point  of  view,  therefore,  we  may  divide  the  teeth  into 
two  classes,  the  temporary  and  the  permanent:  the  first, 
which  have  also  been  called  the  milk  teeth,  are  twenty  in 
number,  are  shed  between  the  age  of  seven  and  fourteen, 
and  are  supplied  by  the  permanent  teeth.  The  temporary 
teeth  are:  eight  incisores,  four  canini,  and  eight  molares,  to 
which  are  added,  between  the  fourth  and  sixth  year,  four 
other  molares,  which  do  not  fall  out,  like  the  preceding, 
and  may  be  considered  as  permanent  teeth.  At  the  age 
indicated  above,  the  twenty  milk  teeth  are  shed  and  are 
succeeded  by  an  equal  number  of  corresponding  perma- 
nent teeth.  The  number  of  these  organs,  which  is  then 
twenty-four,  (counting  the  four  molares  which  remained,) 
afterwards  amounts  to  thirty-two  by  the  development  of 
eight  other  large  molares;  four  of  which  do  not  appear  un- 
til between  the  age  of  eighteen  and  thirty,  and  are  hence 
called  denies  sapientias. 


22fc>  TEGUMENTARY  SYSTEM. 

The  dental  follicles  begin  to  be  apparent  about  the  tenth 
week  of  uterine  life,  but  they  do  not  appear  all  at  the  same 
time.  They  consist  at  first  of  small,  round,  shut  sacs, 
lodged  in  the  alveoli  and  composed  of  two  layers,  an  ex- 
ternal and  an  internal;  the  former  of  which  is  thick  and  in- 
timately adherent  to  the  gums;  the  other,  very  vascular 
and  delicate,  is  a  kind  of  net-work  which  contains  at  first  a 
reddish  fluid,  that  is  gradually  changed  to  a  pale  yellow. 
About  the  fourth  month,  the  bottom  of  this  small  sac  con- 
tains the  generative  pulp,  which  in  a  short  time  assumes  the 
form  of  the  future  tooth.  About  half  the  term  of  utero- 
gestation,  this  pulpy  nucleus  is  covered  by  small  laminoe 
of  ivory  substance,  which  are  soon  after  succeeded  by 
others,  secreted  in  like  manner  upon  the  surface  of  the 
pulp.  So  long  as  this  pulp  is  covered  with  earthy  matter 
only  in  a  small  proportion  of  its  extent,  it  is  easily  to  be 
conceived,  by  the  facility  with  which  it  can  be  separated, 
that  their  bond  of  union  is  merely  inorganic,  and  is 
completely  destroyed  at  a  subsequent  period,  though  they 
can  not  be  possibly  separated,  because  the  ivory  substance 
embraces  every  part  of  the  original  nucleus.  The  part  of 
the  nucleus  which  corresponds  to  the  triturating  surface  of 
the  tooth,  is  the  first  that  is  encrusted  with  the  ivory  sub- 
stance, so  that  its  laminae  are  more  numerous  here  than  in 
any  other  part:  the  roots  are  formed  after  all  the  other 
parts  of  the  teeth,  of  which  they  are  mere  prolongations, 
are  fully  developed.  The  enamel  of  the  teeth  is  secreted 
and  deposited  upon  the  surface  of  the  crown  by  the  inter- 
nal lamina  of  the  sac,  and  is  easily  separated  in  the  foetus 
from  the  ivory  substance.  About  six  or  seven  months  af- 
ter birth,  the  milk  teeth  pierce  the  sac  which  contains 
them,  and  finally  the  mucous  membrane  of  the  gums,  with 
which  the  margins  of  the  orifice  of  the  sac  or  follicle  be- 
come in  a  short  time  confounded:  it  is  at  this  period  that 
the  root  is  developed.  The  different  kinds  of  teeth  are  by 
no  means  formed  simultaneously,  nor  do  they  appear  ex- 


TEGUMENTARY  SYSTEM.  229 

teriorly  at  the  same  time.  According  to  J.  F.  Meckel,  the 
following  general  rules  may  be  established  in  respect  to  the 
development  and  appearance  of  the  teeth:  "  1st,  the  different 
stages  are  regulated  by  the  same  laws,  so  that  the  follicle 
of  the  tooth,  whose  germ  appears  first,  is  also  that  which  is 
first  developed, ossified  and  pierced;  2d,  the  homonymous 
teeth  of  the  same  jaw  generally  correspond;  3d,  the  infe- 
rior teeth  are  developed  before  the  superior,  and  the  ante- 
rior before  the  posterior;  4th,  the  gradual  development  of 
the  human  teeth  corresponds  to  the  permanent  forms  which 
are  found  in  the  scale  of  mammiferous  animals." 

The  follicles  of  the  permanent  teeth  begin  to  appear 
successively  after  the  eighth  month  of  fcetal  life,  and  are 
at  first  situated  in  the  same  alveoli  as  those  of  the  tempo- 
rary teeth,  upon  which  they  are  then  placed,  and  are  united 
with  them  by  their  external  lamina.  These  follicles  are 
soon  after  removed  from  the  milk  teeth,  are  placed  at  their 
posterior  part,  and  are  subsequently  observed  to  be  lodged 
within  particular  alveolar  cavities,  which  result  from  the 
slight  depressions  at  the  posterior  paries  of  the  primary 
cells:  these  depressions  are  converted  into  the  true  alveoli, 
by  the  development  of  a  partition  between  the  follicles  of 
which  we  are  speaking,  and  the  parts  which  are  occupied 
by  the  milk  teeth. — The  milk  teeth  are  shed  in  consequence 
of  the  destruction  of  the  vessels  and  nerves  which  connect 
them  to  the  jaw;  a  destruction  which  is  produced  by  the 
permanent  teeth,  which,  during  the  progress  of  their  de- 
velopment, compress  these  bonds  of  union,  and  destroy  in 
regular  succession  all  the  adhesions  of  the  temporary  teeth, 

The  pulp  of  the  teeth,  whether  permanent  or  temporary, 
is  much  larger  in  proportion  as  it  is  examined  near  the  pe- 
riod of  dentition;  subsequently,  its  vitality  gradually  di- 
minishes, and  is  finally  completely  destroyed:  the  shed- 
ding of  the  teeth  in  advanced  age,  is  a  more  or  less  imme- 
diate consequence  of  this  complete  atrophy  of  their  living 
part,     On  the  other  hand,  the  continual  friction  of  the 


230  TEGUMENTARY  SYSTEM. 

teeth  destroys  by  degrees  their  enamel,  and  exposes  the 
ivory  substance.  Under  these  circumstances  it  sometimes 
happens  that  the  osseous  part  itself  is  worn  away  to  the 
dental  pulp,  which,  in  this  case,  secretes  a  new  osseous  sub- 
stance, which  is  more  soft  than  the  first,  and  serves  the 
purpose  of  filling  up  the  cavit)r  of  the  tooth. 

Function. — The  incisores  and  canini  serve  to  seize  and 
to  rend,  the  mokres  to  triturate  the  food;  neither  of  them 
can,  however,  exclusively  perform  one  of  these  functions. 

Pathological  ./inatomy. 

The  form  of  the  teeth  is  often  very  variable,  and  far  from 
being  in  relation  with  the  normal  type:  the  eminences 
which  surmount  the  crown  may  be  more  numerous  and 
projecting  than  ordinary;  and  the  roots  themselves  may 
present  the  same  kinds  of  anomaly,  or  their  distribution 
may  be  unnatural,*  so  much  so,  that  the  fangs  of  two  con- 
tiguous teeth  may  become  united.  The  number  of  teeth  is 
often  less,  and  sometimes,  though  rarely,  greater  than  that 
which  we  have  indicated;  in  some  instances,  there  is  even 
a  double  row  of  these  organs.  In  general,  the  supernu- 
merary teeth  are  more  common  to  the  superior  than  to  the 
inferior  jaw.  In  some  instances  there  is  a  third  dentition 
a  very  long  time  after  the  second:  the  teeth  are  also  some- 
times transposed;  for  example,  a  molar  tooth  may  occupy 
the  place  of  a  canine,  &c.  The  development  of  the  teeth 
often  takes  place  in  a  preternatural  order;  and  we  not  un- 
frequently  observe  the  persistence  of  one  or  more  of  the 
milk  teeth,  after  the  corresponding  permanent  teeth  have 
been  already  developed,  and  issued  from  their  sockets. 
When  a  tooth  has  been  fractured,  it  does  not  become  con- 

*  In  the  anatomical  museum  of  the  celebrated  Albinus,  is  an  instance 
of  the  body  of  a  molar  tooth  growing  into  the  antrum  highmorianum, 
the  direction  of  the  roots  being  reversed.  Mayo's  Outl.  of  Physiology, 
p.  125.— S.  D.  G. 


TEGUMENTARY  SYSTEM.  231 

solidated,  if  it  is  the  crown  that  has  been  affected;  if  the 
root,  however,  be  injured,  its  proper  membranous  en- 
velope secretes  an  osseous  substance  which  re-unites  the 
fragments. 

Inflammation  of  the  dental  pulp  is  by  no  means  of  rare 
occurrence,  and  occasions  the  most  severe  pain.  It  some- 
times terminates  in  suppuration  or  gangrene,  and  very 
often  in  caries  of  the  affected  tooth :  this  last  disease  attacks 
particularly  the  teeth  which  have  been  deprived  of  their 
enamel,  and  more  frequently  the  molar  teeth  than  any 
other.  The  diseases  of  the  gums  and  the  jaws  may  also 
influence,  in  a  very  considerable  degree,  the  health  of  the 
teeth. 

There  are  sometimes  adventitious  dental  productions, 
especially  in  certain  ovarian  cysts. 

Bibliography  of  the  Tegument ary  System. 

The  works  already  quoted. 

Hebriard.  Memoire  sur  l'analogie  qui  existe  entre  les 
Systemes  muqueux  et  dermo'ide;  Memoires  de  la  Societe 
medicale  d'Emulation,  vol.  VIII,  p.  153. 

Bonn.  De  continuationibus  membranorum.  1763. 

On  the  skin  in  particular. 

Malpighi.  De  exter.  tact,  organ,  in  Epist.  Londres,  1686, 

p.  21—33. 
Gaultier.  Recherches  sur  l'organisation  de  la   Peau   de 

l'homme,  et  sur  les  causes  de  sa  coloration.  Paris,  1805), 

Recherches  sur  l'Organe  cutane.  Paris,  1811. 

Dutrochet.  Observations  sur  la  structure  de  la  Peau,  dans 

le  Journal  complem.,  vol.  V. 
Meckel.  De  la  nature  de  l'Epiderme  et  du  Reseau  qu'on 

appelle  Malpighien;  dans  les  Memoires  de  l'Academie 

de  Berlin.  1753- 
Les  OCuvres  &\<2lbinus  renferment  plusieurs  travaux  sur 


232  TEGT7MENTARY  SYSTEM. 

Panatomie  ties  diverses  couches  cutanees,  sur  les  causes 

dc  leur  coloration,  etc. 
Ch.   Th.  Reus.   De  glandulis  sebaceis  dissert,  etc.   Tu- 

bingse,  1807. 
Hintze.    De  papillis  cutis  tactui   inservientibus.    Leyde, 

1747. 
Meckel.  Nouvelles  observations  sur  Pepiderme,  dans  les 

Memoires  de  Berlin,  ann.  1757. 
Ducrotay  de  Blainville.  Principes  d'anatomie  comparee, 

torn.  I.  Paris,  1S22. 
Gendrin.    Histoire   anatomique   des   inflammations,  t.  I. 

Paris,  1826. 
Bateman.  Abrege  pratique  des  Maladies  de  la  Peau,  tra- 

duit  de  Panglais  par  S.  Bertrand,  in-8vo.  Paris,  1S20. 
Jllibert.  Description  des  maladies  de  la  Peau,  etc.,  gr.  in- 

fol.   Paris,  1S06. 
Precis  theorique  et  pratique  sur  les  maladies  de  la 

Peau,  torn.  I  et  II.  in-8vo.  Paris,  1S22. 
P.  Bayer.  Traite  theorique  et  pratique  des  maladies  de  la 

Peau,  fonde  sur  de  nouvelles  recherches  d'anatomie  et 

de  physiologie,  torn.  I.  in-8vo.,  avec  atlas  idem.  Paris, 

1S26. 

On  the  Mucous  Membrane. 

Peyer.  De  Glandulis  intestinalium.  Amstel.,  1681. 
Brunner.  De  glandulis  duodeni.  Francofurt.,  1715. 
Helvttius.  Mem.  de  l'Academie  royale  des  Sciences.  Paris, 

1721. 
Liebernkuhn.  De  fabr.  et  act.  villos.  intestin.  horn.,  in-4to. 

Lugd.  Bat,  1744. 
H.  Buerger.  Examin  microsc.  villos.  intestin.  cum  icon., 

in-8vo.  Halae,  1819. 
Leuret  et  Lassaigne.  Recherches  physiologiques  et  chim- 

iques  pour  servir  a  Phistoire  de  la  digestion,  in-8vo.  Paris, 

1826. 
Billard.    De  la  Membrane   muqueuse   gastro-intestinale 


TEGUMENT  ART  SYSTEM.  233 

dans  l'6tat  sain  et  dans  l'6tat  inflammatoire,  etc.,  in-8vo. 
Paris,  1825. 
Gendrin.  Ouvr.  cite,  torn.  I. 

On  the  Appendages  of  the  Tegumentary  System. 

1.  The  Hair. 

P.  Chirac.  Letter  a  M.  Regis  sur  la  structure  des  Che- 
veux.  Montpellier,  1688. 

Malpighi.  De  Pilis  observationes,  in  op.  posth. 

Daverney.  (Euvres  anatomiques.  Paris,  1768. 

C.  Jls.  Rudolphi.  Diss,  de  Pilorum  structura.  Grisps- 
wald,  1806. 

Gaaltier.  Ouvr.  cite. 

Heusinger.  Remarques  sur  la  forme  des  Poils,  dans  Jour- 
nal complementaire  du  Dictionn.  des  Sciences  medicales, 
torn.  XIV;  et  sur  la  regeneration  des  poils,  idem,  idem, 
p.  339. 

Plenck.  De  morbis  capillorum,  in  doctr.  de  morb.  cut. 

Meckel.  Memoire  sur  les  Poils  et  les  Dents  qui  se  devel- 
oppent  accidentellement  dans  le  corps;  in  Journ.  com- 
plementaire du  Dictionn.  des  Sciences  medicales,  torn. 
IV,  p.  122—217. 

2.  The  Nails. 

B.  S.  Mbinus.  In  Annot.  acad.  Lib.  II,  cap.  XIV,  de  un- 

gue  humano,  et  cap.  XV,  de  naturS  unguis. 
Ludwig.   De  ortu  et  structure  unguium.  Lips.  1748. 
Haase.  De  nutritione  unguium.  Lips.,  1774. 
Plenck.  De  morbis  unguium;  in  op.  cit. 

3.  The  Teeth. 

«/?.  Serves.  Essai  sur  l'anatomie  et  la  physiologie  des  Dents, 
ou  nouvelle  theorie  de  la  Dentition.  Paris,  1817. 

Geoffroy-St.-Hilaire.  Systeme  dentaire  des  Mammiferes 
et  des  Oiseaux,  embrassant  sous  de  nouveaux  rapports  les 
principaux  faits  de  l'organisation  dentaire  chez  l'homme. 
Paris,  1824. 

31 


234  TEGUMENTARY  SYSTEM. 

J.  Fr.  Meckel.  Essai  sur  le  developpement  des  Dents  chez 

Phomme;   dans  Journal   complementaire  du  Diet,   des 

Sciences  medicales,  torn.  I,  p.  365. 
F.  Cuvier.  Des  Dents  des  Mammiferes,  ets.  Paris,  1822  a 

1825.  Onze  livraisons  in-8vo.,  avec  figures. 
J.  Fox.  Histoire  naturelle  des  maladies  des  Dents  de  l'es- 

pece  humaine,  traduit  de  l'anglais  par  Lemaire.  Paris, 

1821. 
J.  Lemaire.  Traite  sur  les  Dents.  Paris,  1822. 


OF  THE  GLANDULAR  SYSTEM.  235 


CHAPTER  IX. 

OF  THE  GLANDULAR  SYSTEM, 


Definition. — The  glandular  system  consists  of  a  certain 
number  of  organs,  furnished  with  numerous  excretory  ducts 
which  unite  in  one  common  trunk,  in  order  to  terminate 
upon  the  surface  of  the  teguments  and  to  evacuate  the 
fluids  which  are  separated  from  the  blood  in  the  interior 
of  these  organs. 

The  glands  which  properly  belong  to  this  system  are, 
the  three  salivary,  the  lacrymal,  the  liver,  the  pancreas, 
the  mammas,  the  testicles  and  the  ovaria.  * 

*  The  sebaceous  and  mucous  follicles,  as  well  those  which  are  isolat- 
ed as  those  which  occur  in  groups,  as  the  muciperous  glands  of  Peyer, 
(in  the  ilion)  or  rather  those  which  open  upon  the  tegumentary  surface 
by  common  ducts  (lacunse,)  may  be  placed  under  the  same  head  as  the 
glands  that  have  just  been  enumerated,  and  from  which  they  differ 
merely  in  being  less  complicated,  but  being,  like  them,  mere  prolonga- 
tions of  the  teguments.  Indeed,  is  not  a  slight  degree  of  attention  suf- 
ficient to  convince  us  that  there  is  no  essential  difference  between  the 
amygdala  or  the  prostate,  &c,  and  the  lacrymal  or  salivary  glands? 

On  the  other  hand,  the  term  gland  is  sometimes  applied  to  a  number 
of  parts  which  have  only  some  resemblance  as  regards  the  more  gross 
relations  of  form  or  texture.  And  without  speaking  here  of  the  tongue, 
which,  on  account  of  its  rounded  contour,  might  be  placed  in  the  glan- 
dular system,  we  shall  notice:  1st,  the  lymphatic  ganglia,  which  are 
called  conglobate  glands,  in  contra-distinction  of  the  true  organs  of  se- 
cretion, which  are  termed  conglomerate  glands,-  2d,  certain  rounded  or- 
gans, which  are  enveloped  by  a  membrane  which  varies  in  thickness,  and 
sends  prolongations  into  their  interior:  these  organs,  which  Bichat  has 


236  OP  THE  GLANDULAR  SYSTEM. 

Situation  and  arrangement. — The  glands  are  found 
exclusively  in  the  trunk,  and  are  either  in  symmetrical 
pairs,  and  situated  upon  each  side  of  the  mesian  line,  as  the 
lacrymal,  the  salivar)7,  the  mammary,  the  kidneys,  the 
testicles  and  the  ovaries,  or  they  are  single,  and  are  placed 
upon  the  mesian  line,  or  upon  one  side,  as  the  pancreas  and 
the  liver.  •■ 

Conformation. — The  form  of  the  glands  is  very  varia- 
ble; but  they  are  always  more  or  less  rounded,  and  often 
flattened  in  one  or  more  directions.  They  differ  also  still 
further  in  respect  to  their  volume;  what  a  difference  is 
there  between  the  size  of  the  liver,  one  of  the  largest  or- 
gans of  the  body,  and  the  lacrymal  gland? 

Structure. — The  anatomical  composition  of  the  glands 
results,  1st,  from  a  purely  cellular,  or  fibrous  envelope, 
which  is'  in  relation  by  one  of  its  surfaces,  either  with 
cellular  or  adipose  substance,  or  with  a  serous  membrane, 
and  is  confounded  by  the  other  with  the  tissue  of  the  glands; 
2d,  from  vessels,  nerves,  and  excretory  ducts,  whose  most 
minute  ramifications  are  united  by  cellular  tissue  and  form 
the  proper  parenchyma  of  the  organ.  In  all  the  glands, 
except  the  liver  and  the  kidneys,  the  parenchymatous  sub- 
stance is  divisible  into  lobes  and  lobules,  which  result  from 
the  union  of  whitish,  homogeneous  particles.  On  the  con- 
trary, the  organs  to  which  we  have  just  alluded,  are  com- 
posed of  two  substances,  which  are  easily  distinguished  by 

separated  from  the  glandular  system,  are  essentially  vascular,  are  desti- 
tute of  excretory  ducts,  and  are,  according1  to  modern  anatomists,  true 
sanguineous  ganglia,  which  are  analogous  to  the  lymphatic  ganglia,  and 
in  which  the  blood  that  circulates  in  their  interior  is  destined  to  under- 
go a  process  of  perfection.  The  thyroid  and  thymus  glands,  the  spleen 
and  the  capsulx  renales,  compose  the  group  of  these  organs,  which  have 
received  the  name  of  adenoid  or  glandiform  bodies,  and  of  which  we  can 
not  give  a  general  description,  on  account  of  the  diversity  of  their  form, 
their  structure,  and  the  obscurity  in  which  their  true  character  is  still 
involved. 


OF  THE  GLANDULAR  SYSTEM.  237 

the  difference  of  their  colour.  In  the  kidneys,  these  sub- 
stances are  disposed  in  layers,  an  exterior  and  an  interior, 
or  a  cortical  and  a  medullary,  but  in  the  liver,  they  exist 
every  where  simultaneously. 

But  in  what  relations  do  the  most  minute  ramifications 
of  the  vessels  and  of  the  excretory  ducts  stand,  so  as  to 
form  the  proper  tissue  of  the  glands?  Shall  we  admit  with 
Malpighi  that  the  radicles  of  the  excretory  ducts  are  small 
vesicles  or  follicular  pouches,  in  the  parietes  of  which  the 
blood-vessels  terminate;  or  that  the  excretory  ducts  are,  as 
was  asserted  by  Ruisch,  the  immediate  continuation  of  the 
vessels?  Acknowledging  that  this  point  of  minute  anatomy 
is  still  extremely  obscure,  it  is  to  the  first  of  these  hypo- 
theses that  we  would  cede  the  preference,  following  in  this 
respect  the  example  of  the  greatest  modern  anatomists. 
Indeed,  the  study  of  comparative  anatomy  teaches  us  that 
the  glands  are  the  mere  agglomerations  of  numerous  folli- 
cles which  belong  to  the  canalicular  and  ramified  pro- 
longations of  the  tegumentary  membranes.  (i  The  muci- 
perous  glands,  which  are  nothing  but  simple  sacs,  form 
the  prototype  of  the  glandular  formation.  Let  us  imagine 
that  the  branches  of  this  elongated  ramified  sac  unite  with 
those  of  the  vessels,  and  we  shall  have  the  most  intricate 
gland,  without  there  being  any  immediate  communication 
between  the  blood-vessels  and  the  excretory  ducts." — J. 
F.  Meckel. 

The  excretory  ducts,  after  being  successively  joined  so  as 
to  form  large  branches,  finally  unite  in  one  or  more  trunks 
which  terminate  upon  the  surface  of  the  teguments.  In 
their  course,  which  is  sometimes  very  considerable,  the 
trunks  often  present  enlargements,  which  are  small,  as  those 
of  the  mammary  glands,  or  large  and  cystiform,  as  those 
which  constitute  the  gall-bladder  and  the  vesicular  semi- 
nales:  the  urinary  bladder  may  be  considered  as  an  enlarge- 
ment common  to  the  excretory  ducts  coming  from  each  of 
the  kidneys.     The  mucous  membrane,  which  essentially 


238  OF  THE  GLANDULAR  SYSTEM. 

constitutes  the  glandular  apparatus,  gradually  becomes 
thinner  and  more  delicate  in  proportion  as  the  ramifica- 
tions of  the  excretory  ducts  become  more  numerous.  This 
membrane,  however,  is  strengthened  and  protected  by  cel- 
lular substance  which  is  more  or  less  compact,  sometimes 
even  fibro-elastic,  and  in  some  parts  by  a  vascular  erectile 
net-work,  or  muscular  fibres.  The  glands  contain  numerous 
blood-vessels  and  lymphatics;  and  all,  except  the  liver,  re- 
ceive exclusively  arterial  blood.  This  organ  receives,  be- 
sides its  particular  artery,  a  large  venous  trunk  (vena  porta?,) 
which  is  ramified  in  its  substance,  (See  Vas.  Sys. )  In 
general,  the  veins  of  the  glands  do  not  exceed  their  cor- 
responding arteries  in  capacity,  as  is  the  case  in  the  other 
parts  of  the  system;  a  circumstance  which  is  owing  to  the 
loss  which  the  blood,  that  is  carried  to  them  by  the  arteries, 
experiences  in  these  organs. 

Characters,  physical  and  chemical  properties. — Their 
colour,  density  and  consistence,  vary  in  the  different  glands, 
and  can  not  be  described  in  a  general  manner.  The  chemical 
characters  of  the  compound  glands  depend  upon  those  of 
the  elementary  tissues  which  contribute  to  their  formation. 

Vital  properties. — The  glands  appear  to  be  destitute  of 
vital  contractility,  and  in  their  healthy  state,  they  are  but 
little  sensible;  the  testicle  being  the  only  one  that  manifests 
any  considerable  degree  of  sensibility  when  it  is  compress- 
ed. The  presence  of  calculous  concretions  in  the  excretory 
ducts  of  some  of  these  glands,  and  especially  in  those  of 
the  liver  and  the  kidneys,  generally  occasions  severe  pain 
and  distress. 

Differences  according  to  age. — The  glands  in  the  hu- 
man embryo  are  developed  in  passing  through  the  different 
stages  of  complication  which  are  observed  in  the  skin  of 
animals;  and  this  mode  of  development  proves  that  these 
organs  are  nothing  but  more  or  less  complicated  appen- 
dages of  the  tegumentary  system.  Indeed,  the  parts  which 
form  the  excretory  canals  are  perceived  to  be,   at  first, 


OP  THE  GLANDULAR  SYSTEM.  239 

continuous  with  the  teguments,  which  are  afterwards  suc- 
cessively ramified  until  the  gland  is  completely  formed. 
In  the  foetus,  these  kinds  of  glands  are  composed  of  lobes 
and  lobules,  which,  in  some  of  them,  as  in  the  kidneys, 
subsequently  disappear.  The  volume  of  the  glands,  which 
concur  to  the  preservation  of  the  individual,  is  generally 
comparatively  greater  in  the  early  periods  of  life  than  in 
after  age.  On  the  contrary,  the  mammae,  the  testicles  and 
ovaries,  which  are  destined  to  the  preservation  of  the  spe- 
cies, are  usually  small  before  the  age  of  puberty,  when  they 
become  larger  and  acquire  more  vitality:  in  old  age  they 
cease  to  act  and  fall  into  a  kind  of  decay.  The  testicles  and 
the  ovaries,  moreover,  change  their  situation  some  time 
before  birth. 

Functions. — The  glands  serve  to  separate  from  the 
blood,  which  circulates  within  them,  particular  fluids  which 
differ  in  the  different  kinds  of  glands,  and  are  conveyed  to 
the  surface  of  the  teguments  by  the  excretory  ducts.  The 
separation  of  these  products  constitutes  what  is  called  se- 
cretioriy  which  differs  from  the  perspiration  and  follicular 
secretion  only  by  the  intricate  structure  of  the  secretory 
organ.  The  manner,  however,  in  which  the  glandular 
secretion  is  effected,  is  still  unknown,  and  all  the  knowledge 
we  possess  upon  this  subject  is,  that  the  blood,  after  its  ar- 
rival in  the  capillary  arteries,  which  are  distributed  in  the 
proper  substance  of  the  organ,  has  some  of  its  materials  com- 
bined, either  by  virtue  of  a  simple  chemical  re-action  favour- 
ed by  the  dilatory  course  of  this  fluid,  or  under  the  influence 
of  a  vital  action,  exercised  upon  it  by  the  tissue  of  the  follicles 
of  the  gland.  The  changes  in  the  vitality  of  a  gland,  and 
the  state  of  its  nervous  system,  have  a  great  influence  upon 
the  nature  and  the  quantity  of  its  secretion;  and  from  this 
combination  results  a  peculiar  fluid  which  is  discharged 
into  the  excretory  ducts,  and  conveyed  by  them  to  the  sur- 
face of  the  teguments,  or  retained  for  a  certain  time  in  their 
cystiform  cavities.  The  blood,  which  has  not  been  employ- 


240  OF  THE  GLANDULAR  SYSTEM. 

ed  in  the  formation  of  the  humour  to  which  we  have  just 
alluded,  is  taken  up  again  by  the  radicles  of  the  vascular 
centripetal  system. 

Pathological  Anatomy. 

There  are  few  organs  which  present  more  congenial 
anomalies  pf  volume,  form  and  situation,  than  the  glands. 
They  are  often  larger  and  again  much  smaller  than  usual, 
either  primarily,  or,  as  is  most  ordinarily  the  case,  acci- 
dentally: they  are  sometimes  affected  with  atrophy,  which 
may  either  result  from  their  compression,  or  from  the  ces- 
sation of  their  functions.  The  lobular  structure  which  is 
sometimes  observed  to  continue  in  some  of  the  glands,  es- 
pecially in  the  kidneys,  depends  upon  their  imperfect  de- 
velopment. The  kidneys  are  the  organs  which  are  the 
most  subject  to  anomalies  of  number;  thus,  there  have  been 
instances  where  there  was  sometimes  but  one,  and  at  others, 
three  of  these  glands.  The  ovaries  and  the  testicles  are 
sometimes  entirely  wanting;  and  their  situation  also  may 
be  anomalous:  thus,  there  have  been  instances  where  the 
ovaries  passed  out  of  the  abdomen,  and  where  one  or  both 
testicles  remained  in  that  cavity,  after  the  time  when  they 
ought  to  have  descended  into  the  scrotum,  and  even  dur- 
ing life. 

The  solutions  of  continuity  of  the  glands  cicatrize  with 
difficulty,  and  have  a  tendency  to  become  fistulous,  because 
the  secretions,  flowing  continually,  prevent  the  re-union 
and  agglutination  of  the  lips  of  the  wound. 

The  glands  are  extremely  subject  to  inflammation;  and 
this  morbid  state  is  capable  of  producing  different  pheno- 
mena in  the  different  kinds  of  glands,  and  even  of  being 
propagated  to  the  tegumentary  membrane.  It  suspends, 
augments,  or  alters  their  secretion,  and  often  induces  the 
induration  of  their  tissue  by  the  exhalation  of  an  albumin- 
ous or  sanguineous  fluid  during  the  inflammatory  process. 
This  induration,  which  ordinarily  accompanies  the  oblite- 


OP  THE  GLANDULAR  SYSTEM.  241 

ration  of  at  least  a  part  of  the  excretory  ducts,  often  be- 
comes schirrous  or  carcinomatous,  when  the  inflammation 
continues  to  exist:  these  alterations  are  frequently  conse- 
quences of  chronic  inflammations  of  the  mammae,  the  tes- 
ticles and  the  ovaries,  The  glandular  tissue  is  never  pro- 
duced accidentally;  but  the  different  transformations  and 
accidental  productions  are  observed  in  all  of  them,  and  par- 
ticularly in  the  mammae,  the  testicles  and  the  ovaries. 

Bibliography. 

The  treatises  on  general  anatomy  already  quoted. 
M.  Malpighi.  De  viscerum  structural,  cap.  II,  in  op.  omn. 

De  gl.  conglob.  Ep.,  p.  6.  Opera  posth. 
H.  Bcerhaave  et  Ruisch.  De  structura  glandul.,  etc. ;  in 

Ruisch  op.  omn. 
Th.  JBordeu.  Recherches  anatomiques  sur  les  Glandes. 

Paris,  1751. 
G.  «#.  Haase.  De  Glandularum  definitione.  Lips.,  1804. 


32 


542  MUSCULAR  SYSTEM. 


CHAPTER  X. 


MUSCULAR  SYSTEM. 


SECTION  1. 

General  Observations. 

Definition. — This  system  consists  of  an  assemblage  of 
organs — the  muscles — which  compose  the  greater  part  of  the 
body,  are  characterized  by  a  more  or  less  evidently  fibrous 
structure,  and  by  extensive  contractions,  by  virtue  of  which 
they  are  the  agents  of  locomotion. 

Division. — Bichat,  struck  with  differences  of  form,  the 
organization  and  functions  which  exist  between  the  exte- 
rior voluntary,  and  the  interior  membraniform  involuntary 
muscles,  established  two  muscular  systems,  which  he  de- 
signated according  to  their  most  prominent  and  distinctive 
characters,  by  the  nanies  of  the  muscular  system  of  ani- 
mal life,  and  the  muscular  system  of  organic  life.  More 
lately,  anatomists,  aware  that  the  relations  which  exist  be- 
tween these  two  systems  in  respect  to  their  organization, 
their  properties,  &c,  are  too  important  to  be  separated  in 
an  absolute  manner,  have  united  them  under  the  common 
denomination  of  the  muscular  system,  and  have  divided 
the  muscles  themselves  into  two  classes. 

Structure. — The  muscles  consist  of  an  assemblage  of 
primitive  microscopic  fibres  united  in  fasciculi,  which  are 
easily  distinguishable  by  the  naked  eye  (secondary  fibres); 
but  these  fasciculi  form  still  larger  ones,  which,  by  uniting 


MUSCULAR   SYSTEM.  243 

with  others,  form  the  muscles.  In  order  to  perceive  the 
fasciculi,  it  is  necessary  to  subject  a  muscle  to  the  action 
of  ebullition;  we  shall  then  be  able  easily  to  detach  them 
under  the  form  of  flattened  or  prismatic  filaments,  which 
extend  either  throughout  the  whole  length  of  the  muscle, 
or  they  terminate  before  they  arrive  at  its  extremity,  by 
uniting  with  the  tendons  or  the  aponeuroses.  The  fila- 
ments, or  secondary  fibres  which  compose  the  fasciculi,  are 
always  parallel,  but  this  is  seldom  the  case  with  the  fasci- 
culi which  compose  the  body  of  a  muscle;  they  being 
almost  always  oblique  in  respect  to  each  other.  Ex- 
amined with  the  microscope,  the  fibres,  like  the  fasciculi, 
present  still  smaller  fibres,  which  appear  to  be  the  ultimate 
parts  of  the  muscles,  and  are  hence  called  the  elementary 
or  primitive,  or  simply  the  muscular  fibres.  The  phy- 
siologists who  have  paid  particular  attention  to  the  struc- 
ture of  the  muscular  fibre,  are  Prochaska,  the  Wenzells, 
Autenricth,  Sprengel,  Mr.  Bauer,  and  Sir  E.  Home, 
Messrs.  Dumas  and  Prevost,  and  M.  Dutrochett.  In  the 
present  day  these  fibres  are  generally  regarded  as  small, 
somewhat  flattened  filaments,  having  every  where  the  same 
diameter,  and  being  composed  of  a  series  of  globules  which 
are  exactly  analogous  to  the  white  globules  of  the  blood, 
and  are  united  together  by  a  perfectly  transparent  mucous, 
or  gelatinous  substance.  Every  thing  else  that  anatomists 
have  advanced  upon  the  ultimate  structure  of  the  muscular 
fibre,  is  of  a  hypothetical  nature.  The  muscular  fibre,  and 
consequently  the  secondary  fibres,  and  the  fasciculi,  pre- 
sent, when  they  contract,  transverse  wrinkles,  which  are 
nothing  but  temporary  folds  that  disappear  as  soon  as  the 
cause  of  contraction  is  removed.  These  phenomena  are 
more  conspicuous  in  the  belly  of  the  muscle  than  at  its 
extremities,  which  are  both  drawn  towards  its  middle. 

Besides  the  proper  substance  of  the  muscles,  which  ap- 
pears to  be  formed  of  globules,  and  the  transparent  medium 
in  which  they  are  disposed  in  linear  orders,  these  organs 


244  MUSCULAR  SYSTEM. 

contain  cellular  tissue,  blood-vessels,  lymphatics,  and 
nerves.  The  cellular  tissue  forms  a  general  covering  (or 
the  muscles,  dips  into  their  substance,  and  forms  a  sheath 
for  each  fasciculus,  and  probably  for  each  elementary  fibre: 
here,  however,  the  existence  of  the  cellular  substance  can 
only  be  admitted  by  analogy.  The  tenuity  and  consistence 
of  this  substance  gradually  diminish,  in  proportion  as  its 
divisions  become  more  minute.  (V.  His.  of  Int.  C.  Tissue.) 
Adipose  substance  also  occurs  in  the  interior  of  the  mus- 
cles, between  their  fasciculi,  and  even  between  their  se- 
condary fibres. 

The  number  and  caliber  of  the  vessels  of  the  muscles  are 
considerable,  and  are  proportionate  to  the  volume  of  the 
different  muscles  which  compose  the  two  classes  of  the 
muscular  system.  The  arteries  having  reached  the  cel- 
lular envelope  of  these  organs,  divide  into  numerous 
branches,  which  are  distributed  in  different  directions,  be- 
tween the  fasciculi,  and  terminate  by  successive  ramifica- 
tions in  the  cellular  tissue,  and  the  secondary  fibres,  be- 
yond which  they  can  not  be  traced:  we  are  still  ignorant 
of  the  relations  which  exist  between  the  elementary  fibres, 
and  the  blood-vessels  of  the  muscles.  The  muscles  have 
but  few  lymphatic  vessels;  and  the  veins,  which  are  larger 
and  more  numerous  than  the  arteries,  are  divided  into  su- 
perficial and  deep  seated;  the  latter  of  which  generally  ac- 
company the  arteries.  It  is  not,  however,  to  the  presence 
of  these  numerous  vessels,  but  to  another  cause,  which  we 
shall  hereafter  point  out,  that  we  are  to  attribute  the  colour 
of  the  muscles;  for  this  is  not  in  relation  with  the  quantity 
of  the  blood  which  penetrates  these  organs;  it  remains,  not- 
withstanding the  changes  which  the  colour  of  the  blood 
experiences  in  cases  of  suffocation.  The  nerves  of  the 
muscles  are  exceedingly  numerous,  and  are  derived,  either 
from   the  encephalo-rachidian    masses,  or  from   the  gan- 


MUSCULAR  SYSTEM,  245 

glionic  system,  accordingly  as  these  muscles  belong  to  the 
first  or  to  the  second  class  of  the  muscular  system.* 

In  some  instances  the  same  muscle  receives  several 
nerves  from  different  origins:  in  this  case  it  appears,  ac- 
cording to  the  researches  of  Mr.  C.  Bell,  that  the  plurality 
of  the  nerves  is  not  intended  for  the  accumulation  of  a 
greater  quantity  of  the  nervous  energy  in  the  muscle,  but 
to  enable  it  to  perform  several  kinds  of  motion.  Let  this, 
however,  be  as  it  may,  it  is  certain  that  the  nerves  general- 
ly enter  the  muscles  by  following  the  course  of  the  blood- 
vessels, proceeding  either  parallel  with,  or  perpendicularly 
to  the  fasciculi  and  muscular  fibres,  in  which  they  soon  be- 
come undistinguishable.  The  imagination  of  the  anato- 
mist has  supplied  what  inspection  can  not  demonstrate  in 
respect  to  the  termination  of  the  nervous  filaments,  and  he 
has  supposed  that  the  substance  of  the  nerves  is  either 
lodged  in  the  cellular  tissue,  and  communicates  to  it  its 
conducting  property  (Isenflamm),  or  that  a  nervous  atmo- 
sphere, emanating  from  these  filaments,  extends  from  the 
seat  of  innervation  to  their  termination. 

According  to  the  microscopic  observations  of  MM. 
Prevost  and  Dumas,  it  appears  that  the  nerves  of  the  mus- 
cles extend  farther  than  they  can  be  traced  by  the  naked 
eye;  that  after  a  nerve  has  ramified  a  certain  number  of 
times,  it  becomes  expanded,  and  that  its  secondary  fasci- 
culi shoot  out,  and  give  off  filaments  which  traverse  the 
muscular  fibres  at  a  right  angle,  and  either  form  a  kind  of 
loop  and  return  to  the  same  nerve,  or  anastomose  with  the 
neighbouring  branches.  These  transverse  filaments  are 
very  numerous  and  near  each  other;  and,  in  general,  the 
small  nerves  which  furnish  them  proceed  parallel  with  the 
muscular  fibres;  and  in  some  instances  two  of  them  pass 
together,  and  in  such  a  manner  as  to  give  off  an  equal  num- 

*  We  have  already  seen  to  what  part  of  the  cerebro-spinal  masses  the 
nerves  correspond  which  preside  over  the  voluntary  motions, 


241)  MUSCULAR  SYSTEM. 

ber  of  filaments  which  intersect  the  muscular  fibres  per- 
pendicularly. From  these  observations  it  would  really  ap- 
pear, that  the  nerves  have  no  termination,  since  their  ulti- 
mate divisions  anastomose  with  the  neighbouring  branches, 
or  return  to  join  their  original  trunk. 

Characters,  physical  and  chemical  properties. — The 
colour  of  the  muscles  varies,  according  to  the  class  to  which 
the}7  belong,  from  a  grayish  white  to  a  deep  red;  and  ap- 
pears to  be  much  more  intense  in  proportion  as  the  muscle 
is  thick  and  large;  there  being  scarcely  any,  where  the  fibres 
are  isolated.  The  colour  of  the  muscles  does  not  depend  upon 
their  vascularity,  but  upon  the  presence  of  a  colouring  mat- 
ter which  is  analogous  to  that  of  the  blood:  by  washing  a 
portion  of  muscle,  the  colouring  matter  will  remain  sus- 
pended in  the  water;  it  may  also  be  readily  separated  by 
boiling,  and  when  a  muscle  is  exposed  to  putrefaction,  it 
immediately  disappears. 

The  muscular  fibre  is  semi-transparent,  soft,  slightly 
elastic,  endowed  with  the  power  of  resisting  considerably 
during  life,  especially  during  its  state  of  contraction,  and 
enjoying  a  remarkable  degree  of  contractility.  By  slow 
desiccation  it  is  rendered  more  prominent,  transparent,  and 
hard.  After  death  the  muscular  fibre  yields  readily  to 
such  efforts  as  have  a  tendency  to  break  it. 

The  action  of  ebullition,  the  dilute  acids,  alkohol,  and  the 
different  saline  solutions,  render  the  muscles  more  consist- 
ent and  more  evidently  fibrous.  The  chemical  analysis  of 
muscular  flesh  has  furnished  the  carbonate  and  phosphates 
of  lime,  of  soda  and  ammonia,  a  small  quantity  of  albumen, 
gelatine,  osmazome,  and  a  considerable  proportion  of  fibrin. 

The  marked  predominence  of  the  fibrin  in  the  chemical 
composition  of  the  muscles,  establishes  a  very  striking 
relation  between  them  and  the  clot  of  the  blood,  and  tends  to 
prove,  that  the  sanguineous  globules  and  those  of  the  mus- 
cular fibre,  which  are  already  identical  by  their  form,  are 
also  bv  their  chemical  nature. 


MUSCULAR   SYSTEM.  247 

Vital  properties  and  f mictions. — The  muscles  possess 
a  middle  degree  of  sensibility  in  the  healthy  state,  but  in 
certain  morbid  affections,  especially  in  inflammations,  their 
sensibility  becomes  considerably  exalted.  They  enjoy  the 
highest  degree  of  vital  contractility  or  irritability 
(Haller,)  a  property  upon  which  depends  the  character 
which  they  enjoy  in  the  animal  economy. 

What  are  the  phenomena  of  this  contractility  of  the 
muscles,  or  rather  what  is  contraction?  When  a  muscle 
acts  it  becomes  shorter  and  thicker,  as  well  as  more  dense 
and  hard.  The  first  of  these  phenomena  being  the  most 
important,  and  the  others  being  mere  consequences,  it  is  it 
which  has  induced  physiologists  to  give  to  the  muscular 
action  the  name  of  contraction.  It  has  been  often  asked 
whether,  during  contraction,  the  muscles  gain  exactly  in 
thickness  what  they  lose  in  length;  and  whether  their  vo- 
lume augments,  diminishes,  or  remains  the  same.  The 
best  conducted  and  most  satisfactory  experiments  upon 
this  subject,  and  amongst  others,  those  of  MM.  Meckel, 
Prevost  and  Dumas  are  favourable  to  the  last  hypothesis. 
When  the  muscles  contract,  they  become  corrugated,  but 
do  not  undergo  any  change  of  colour,  as  has  been  supposed 
by  some  anotomists. — Having  thus  briefly  pointed  out  the 
changes  which  a  muscle  experiences  when  in  a  state  of  ac- 
tion, we  shall  next  inquire  what  phenomena  takes  place  in 
the  different  parts  of  the  muscles?  The  muscular  fibres 
are  drawn  in  a  zigzag  direction  throughout  the  whole  ex- 
tent of  their  length,  and  this  in  such  a  manner  that  the 
apaces  of  the  sinuositus. which  they  form  are  always  the 
points  where  the  nervous  filaments  intersect  the  fibres  at  a 
right  angle,  (Prevost  and  Dumas)  so  that  the  contraction  is 
owing  to  the  sinuous  direction  of  the  muscular  fibres.  Phy- 
siologists have  endeavoured  to  determine  the  extent  of  the 
shortening  which  the  muscular  fibre  experiences:  during  the 
state  of  contraction,  according  to  Bernouilli,  it  is  as  one 
third  to  that  of  the  fibre:  while  Prevost  and  Dumas  esti- 


248  MUSCULAR  SYSTEM. 

mate  it  at  one  fourth,  according  to  the  extent  of  the  angles 
formed  by  the  zigzag  direction  of  the  fibre, — a  fact  which 
is  confirmed  by  direct  observation.  The  possible  degree 
of  rapidity  of  muscular  contraction  varies  in  the  different 
muscles;  but  it  is  always  considerable.  In  certain  muscles, 
a  part  of  the  fibres  remain  at  rest  while  the  others  contract: 
this  phenomenon  is  chiefly  observed,  as  has  been  proved  by 
the  experiments  of  Mr.  C.  Bell,  in  those  muscles  which 
receive  their  nerves  from  different  sources. 

When  the  muscles  contract,  they  acquire  elasticity,  and 
the  force  which  they  sometimes  display  during  this  state, 
is  so  great  as  to  break  their  connexions  with  the  tendons 
and  the  bones:  this  force  is  in  direct  ratio  with  the  number 
of  their  fibres. 

Physiologists  have  at  all  periods  endeavoured  to  explain 
muscular  contraction,  and  have  assigned  to  this  phenome- 
non, either  mechanical  or  chemical  causes,  according  to 
the  prevailing  theories  of  the  time.  Haller,  after  having 
refuted  such  explanations  as  these,  thought  he  had  ascer- 
tained the  true  cause  of  contraction,  and  asserted  that  it 
took  place  by  virtue  of  a  peculiar  property,  which  he  term- 
ed irritability,  and  which  since  the  time  of  Bichat, 
has  received  the  name  of  contractility:  but  this  was 
merely  expressing  a  fact  in  an  abstract  manner,  and  not 
explaining  it.  It  is  to  MM.  Prevost  and  Dumas  that  we  are 
indebted  for  the  most  ingenious  hypothesis  that  has  hither- 
to been  proposed  upon  this  subject.  These  experimenters 
assert,  as  we  have  already  had  occasion  to  state,  that  the 
nervous  filaments,  which  are  distributed  to  the  muscles,  in- 
tersect their  fibres  at  a  right  angle,  and  are  of  opinion,  that 
these  filaments  are  traversed  by  a  current  of  galvanic  fluid 
which  attracts  them  towards  each  other,  and  that  this  at- 
traction is  the  cause  of  the  zigzag  direction  of  the  fibres  to 
which  the  nerves  are  attached.  According  to  this  theory 
the  muscular  fibres  are  passive  in  the  phenomena  of  con- 
traction, while  the  nerves  themselves  are  the  true  agents. 


MUSCULAR  SYSTEM.  249 

Several  physiological  and  pathological  facts  also  go  to  sup- 
port this  explanation.  The  analogy  which  is  supposed  to 
exist  between  the  cause  of  the  vital  contraction  of  the  mus- 
cles and  that  of  the  phenomena  of  galvanism,  would  appear 
evident  by  the  contractions  which  a  dead  muscle,  or  sim- 
ply its  nerves  manifest  when  they  are  exposed  to  the  ac- 
tion of  the  galvanic  pile.  These,  however,  are  mere  hy- 
potheses, and  in  the  present  state  of  our  knowledge  we  are 
still  ignorant  of  the  proximate  cause  of  muscular  contrac- 
tion; though  it  is  otherwise  with  regard  to  the  conditions 
of  the  muscles  themselves;  for  we  know,  1st,  that  it  is  ne- 
cessary for  a  muscle,  in  order  to  produce  vital  contrac- 
tions, to  be  (a)  in  a  healthy  state;  (b)  that  its  communica- 
tions with  the  heart  by  means  of  the  vessels,  and  with  the 
nervous  centre  by  means  of  its  nerves,  should  not  be  in- 
terrupted ;  and  (c)  that  when  the  nervous  centre  is  in  a  state 
of  disease  it  suspends  its  influence  upon  the  muscles.  2d. 
In  order  that  contraction  may  take  place,  it  is  necessary 
there  should  be  an  exciting  cause;  this  does  not  always  ex- 
ist, nor  is  it  the  same  in  all  the  muscles.  Thus,  the  will 
acts  only  upon  the  muscles  of  the  first  class,  while  all  those 
of  the  second  contract  under  the  influence  of  the  moral  af- 
fections, the  irritation  of  the  encephalic  centre,  the  stimulus 
of  the  internal  and  the  external  teguments,  the  sthenic  state 
of  the  membranes,  or  the  cellular  envelope  of  the  muscles, 
and  under  the  direct  mechanical,  chemical,  or  galvanic  ex- 
citement of  the  muscles,  or  of  their  nerves  alone. 

When  the  cause  of  contraction  ceases  to  act,  the  organ 
recovers  its  primary  dimensions,  a  phenomenon  which 
some  anatomists  consider  as  a  vital  action,  and  not  as  the 
simple  effect  of  the  elasticity  of  the  fibres;  this  opinion, 
which  is  entertained  by  J.  F.  Meckel,  does  not  appear  to 
be  more  plausible  than  that  of  Berthez,  who  attributes  to 
the  muscles  a  power  of  fixed  situation. 

Mode  of  development  and  differences  according  to 

age. — At  the  commencement  of  uterine  life,  the  muscles 
33 


250  MUSCULAR  SYSTEM. 

are  confounded  in  the  mucous  mass  which  represents  the 
cellular  tissue:  their  fibrous  structure  is  not  distinct  until 
about  the  third  month;  but  the  pulsations  of  the  heart, 
which  begin  at  a  much  earlier  period,  indicate  a  preco- 
cious organization  of  the  tissue  of  this  organ.  The  mus- 
cles are  at  first  soft,  gelatinous,  and  ver}-  pale.  According 
to  Bichat,  their  galvanic  irritability  is  much  less  during 
foetal  life  than  in  the  subsequent  periods;  while  the  experi- 
ments of  M.  Meckel  go  to  prove  the  contrary. 

During  infancy,  the  muscles  are  still  pale  and  soft,  and 
have  a  much  smaller  proportion  of  fibrin  than  subsequent- 
ly; though  their  movements  are  more  prompt  and  easy 
than  in  the  following  periods  of  life.* 

In  the  adult,  the  muscles  are^>t  the  maximum  of  their 
colour,  their  fibrinous  composition  and  vital  energy;  their 
form  is  more  distinct;  their  movements  less  rapid,  but 
more  sure  and  steady  than  in  the  infant.  In  old  age,  the 
muscles  become  pale  and  acquire  a  certain  degree  of 
hardness  and  rigidity,  and  their  contractions  also  become 
slow  and  feeble.  In  the  female  the  muscles  are,  cce.te.ris 
paribus,  rounder,  more  soft,  and  less  powerful  than  in 
the  male;  and  their  contractions  are  also  more  feeble  and 
rapid. 

There  do  not  appear  to  be  any  other  differences  be- 
tween the  different  varieties  of  the  human  races,  in  relation 
to  the  muscular  system,  than  those  which  generally  result 
from  the  health  of  the  individual  and  his  mode  of  living: 
civilized  people,  therefore,  enjoy  a  very  marked  superior- 
ity over  savages,  in  respect  to  the  development  and  energy 
of  their  muscles. 

After  death,  the  muscles  may  be  observed  to  contract, 
during  a  certain  time,  under  the  influence  of  certain  stimu- 

•  Supposing  that  this  circumstance  is  concomitant  with  the  imper- 
fection of  the  organization  of  the  muscular  fibre,  and  with  a  great  sus- 
ceptibility of  the  nervous  organs,  we  are  induced  to  regard  these  last  as 
the  true  agenis  of  contraction. 


MUSCULAR  SYSTEM.  251 

li;  but,  as  regards  this,  it  is  to  be  remarked,  1st,  that  the 
time,  during  which  the  muscles  remain  sensible  to  artifi- 
cial excitement,  varies  in  the  different  muscles;  2d,  that 
all  of  them  cease  to  be  irritable  to  the  action  of  one  stimu- 
lus, while  they  are  still  so  to  another,  and  that,  in  this 
respect,  the  organs  of  which  we  are  treating  can  not  all  be 
placed  in  the  same  class;  thus,  the  heart  is  still  irritable 
under  the  influence  of  mechanical  agents,  after  it  has  ceas- 
ed to  be  so  by  the  galvanic  action,  even  after  the  contrac- 
tility has  been  exhausted  in  every  other  part  of  the  system: 
on  the  contrary,  the  exterior  muscles  are  still  irritable  by 
the  action  of  the  galvanic  pile  after  they  have  ceased  to  be 
so  by  mechanical  agents.* 

The  muscular  contractility  remains  until  about  twenty- 
four  hours  after  death.  The  cause  of  this,  and  the  prior 
state  of  the  subject  greatly  influence  the  irritability  of  the 
muscles  in  the  dead  subject.  When  the  subject  has  died 
suddenly  in  consequence  of  violence,  or  apoplexy,  and  all 
other  things  being  equal,  the  muscles  retain  their  irrita- 
bility for  a  much  longer  time  than  under  ordinary  circum- 
stances. When  the  passage  from  life  to  death  has  been 
less  sudden,  the  muscles  contract  a  much  longer  time  un- 
der the  influence  of  external  excitants,  in  proportion  as 
the  disease  has  been  less  protracted,  and  has  had  less  influ- 
ence upon  the  assimilative  process.     In  persons  who  die 

*  Several  experimenters  have  endeavoured  to  point  out  the  order  of 
succession  in  which  the  muscles  cease  to  be  capable  of  contracting1. 
Haller,  Frosiep,  and  Nysten,  have  left  us  different  results  upon  this  sub- 
ject. Those,  however,  which  the  latter  physiologist  has  obtained  from 
his  experiments  upon  decapitated  subjects  and  upon  animals,  appear  to 
deserve  the  most  confidence.  According-  to  him,  the  irritability  leaves 
successively  the  aortic  ventricle,  the  large  intestine,  the  small  intestine 
and  the  stomach,  the  urinary  bladder,  the  pulmonic  ventricle,  the  oeso- 
phagus, the  iris,  the  exterior  muscles  of  the  trunk,  those  of  the  inferior 
extremities,  and  finally  those  of  the  superior  extremities,  and  the  right 
and  the  left  auricles. 


252  MUSCULAR  SYSTEM. 

from  the  action  of  the  deleterious  gases,  such  as  the  car- 
bonic, the  sulphurous,  the  hydro-sulphurous,  &c,  or  from 
the  stupifying  poisons,  the  muscular  irritability  promptly 
disappears. 

When  the  muscles  are  no  longer  susceptible  of  contract- 
ing under  the  influence  of  stimuli,  they  become  rigid  and 
cold.  Nysten  considers  the  first  of  these  effects  as  the  last 
phenomenon  of  irritability,  an  opinion  which  is  contradict- 
ed by  that  which  regards  the  nerves  as  the  true  organs 
of  muscular  contractions:  indeed,  the  cadaverous  rigidity 
of  the  human  subject,  and  in  the  scale  of  animals,  is  much 
harder  and  more  precocious  as  the  nerves  lose  more  rapid- 
ly ther  galvanic  excitability.  This  fact  would  induce  us 
to  believe  that  the  phenomenon  to  which'  we  have  just  al- 
luded has  no  analogy  with  the  true  muscular  contractions; 
perhaps  we  ought  rather  to  refer  it  to  those  contractions 
which  are  observed  by  dividing  certain  tissues  in  the  dead 
body,  and  which  the  immortal  Haller  has  attributed  to  a 
vis  mortua,  and  Bichat  to  the  contractility  of  tissue,  both 
of  which  are,  however,  by  no  means  capable  of  affording 
the  true  explanation.  The  muscular  contractions  have  for 
their  object,  either  to  impart  movements  to  the  solids  or 
fluids,  or  to  maintain  them  in  their  proper  situation.  The 
mode  of  action  of  the  muscles  and  the  great  variety  of  its 
results  depend  upon  the  number,  the  disposition  and  length 
of  the  fibres  and  fasciculi,  &c;  but  chiefly  upon  the  state  of 
firmness  or  degree  of  mobility  of  the  points  to  which  they 
are  attached. 

The  muscles  are  called  congeners  or  antagonists,  accord- 
ingly as  they  act  in  the  same  or  in  opposite  directions.  The 
antagonism  is  chiefly  observed  between  the  muscles  of  the 
first,  but  sometimes  also  between  those  of  both  classes,  as 
for  instance,  between  the  sphincters  and  the  muscles  of 
the  fecal  and  urinary  excretions.  The  contraction  of  one 
muscle  is  always  accompanied  by  that  of  its  congeners,  and 
by  the  relaxation  of  its  antagonists. 


MUSCULAU    SYSTEM.  253 


Pathological  Jlnatomy. 

The  muscles  sometimes  present  mal-conformations  which 
are  almost  always  congenital,  and  consist  chiefly  in  an  ex- 
cess or  defect  of  length,  divisions,  anomalies  of  attachment 
&c.  They  are  frequently  observed  to  be  in  a  state  of  atro- 
phy and  hypertrophy:  the  first  is  the  result  of  their  want 
of  action,  and  is  chiefly  observed  in  cases  of  paralysis,  or 
where  the  muscle  has  been  exposed  to  protracted  compres- 
sion; the  second  is  the  effect  of  too  severe  exercise,  and  is 
observed  only  in  the  interior  muscles,  and  especially  in  the 
heart.  The  displacement  (luxation)  of  the  muscles  has  only 
been  observed  in  cases  where  the  aponeurotic  envelopes  of 
the  muscles  were  divided.  The  muscles  are  sometimes 
susceptible  of  experiencing  transverse  ruptures  in  conse- 
quence of  violent  contractions,  either  of  themselves,  or  of 
their  antagonists,  or  under  the  influence  of  sudden  and  ex- 
cessive extension:  these  solutions  of  continuity,  however, 
chiefly  result  from  the  violent  contractions  of  the  muscles 
at  the  point  of  union  of  the  muscular  fibres  with  the  ten- 
dons, or  the  aponeuroses  of  insertion.  The  heart  is  some- 
times ruptured  in  consequence  of  its  violent  contractions, 
in  certain  cases  of  dilatation  of  its  cavities  (aneurism),  es- 
pecially if  its  parietes  are  at  the  same  time  thin  and  weak. 

When  a  muscle  has  been  divided  transversely,  either  in 
consequence  of  rupture,  or  by  a  cutting  instrument,  the 
borders  of  the  solution  of  continuity  separate,  and  imme- 
diate re-union  can  not  be  effected;  but  the  extremities  of 
the  organ  secrete  a  fluid  which  fills  up  the  space  between 
them,  becomes  organized,  and  ordinarily  acquires  the  tex- 
ture and  appearance  of  fibrous  tissue.  This  intermediate 
tendinous  part,  at  once  isolates  and  re-unites  the  two  parts 
of  the  muscle;  but  we  are  ignorant  whether  they  both  con- 
tinue to  contract.  Be  this  as  it  may,  it  is  evident  that  the 
movements  which  are  produced  by  the  muscles  thus  re- 


254  MUSCULAR  SYSTEM. 

united,  are  for  a  long  time  feeble,  and  seldom  recover  com- 
pletely, their  former  extent  and  firmness. 

It  is  supposed  that  in  proportion  as  the  separation  and 
the  tendinous  part  of  the  muscle  are  more  considerable,  the 
longer  and  the  more  imperfect  will  be  the  re-establishment 
of  its  motions.  Moreover,  as  the  tendinous  part  never  ac- 
quires all  the  firmness  and  resistance  of  the  muscular  fibre, 
and  as  it  remains  extensible,  it  neutralizes  in  great  mea- 
sure the  effects  of  the  contraction  of  the  muscle.  Wounds 
of  the  muscles  which  are  attended  with  denudation  and 
loss  of  substance,  are  covered  by  a  cicatrix,  which  results 
from  a  process  similar  to  that  which  we  have  described  in 
the  first  chapter. 

Inflammation  of  the  proper  substance  of  the  muscles  is 
still  doubted;  but  their  cellular  tissue  is  often  inflamed,  as 
is  satisfactorily  proved  by  the  collections  of  purulent  mat- 
ter which  are  observed  between  their  fasciculi.  In  some 
instances,  the  muscles  are  remarkably  flaccid  and  pale;  and 
we  not  unfrequently  meet  with  a  gelatinous  substance  be- 
tween their  fasciculi  and  fibres,  in  consequence  of  rheuma- 
tism. Are  the  fatty  transformations  of  the  muscles  only 
apparent,  as  is  supposed  by  Beclard,  and  do  they  consist 
merely  in  a  preternatural  development  of  the  inter-fasci- 
cular  adipose  tissue  of  these  organs,  in  those  cases,  where 
their  pale  and  shrivelled  fibres  are  easily  confounded  with 
the  adipose  substance? 

The  muscular  tissue  is  seldom  affected  with  schirrous 
and  carcinomatous  degenerations;  and  as  to  its  accidental 
development,  all  the  cases  that  have  been  noticed  may  evi- 
dently be  referred  to  morbid  productions,  whose  appear- 
ance created  some  illusion.  May  we  consider  with  some 
physiologists,  the  development  of  the  muscular  texture  of 
the  uterus  during  pregnancy  as  a  kind  of  temporary  acci- 
dental production? 


MUSCULAR  SYSTEM.  255 

SECTION   2. 

Of  the  Exterior  Muscles. 

Synonyma.-  Voluntary  muscles,  muscles  of  animal  life  (Bichat),  muscles, 
properly  so  called. 

Definition. — The  exterior  muscles  are  those  which,  be- 
ing spread  beneath  the  external  tegumentary,  and  around 
the  osseous  system,  are  subject  to  the  will. 

Situation. — The  exterior  muscles  are  in  relation  with 
the  osseous  or  cartilaginous  parts  of  the  skeleton,  with  the 
skin,  the  cartilages  of  the  larynx,  the  organs  of  the  senses, 
and  with  the  orifices  of  the  digestive,  the  genital  and  urin- 
ary passages.  Most  of  these  muscles  are  in  pairs,  and  are 
situated  on  each  side  of  the  body,  some,  however,  are  sin- 
gle, and  extend  from  the  mesian  line  to  either  side. 

Number. — Anatomists  are  not  agreed  as  to  the  number 
of  the  exterior  muscles;  some  include  in  one  the  fasciculi, 
which  others  regard  as  so  many  distinct  muscles;  according 
to  the  differences  of  their  calculations,  they  vary  in  num- 
ber from  three  to  four  hundred. 

Volume,  form,  and  arrangement. — There  is  a  very 
great  difference  between  the  volume  of  the  different  mus- 
cles: to  be  convinced  of  this,  it  is  only  necessary  to  com- 
pare the  triceps  cruralis,  and  some  of  the  other  large  mus- 
cles of  the  trunk,  with  the  small  muscles  of  the  bones  of 
the  ear.  The  muscles,  like  the  bones,  may  be  divided 
according  to  their  form,  into  long,  flat,  and  short.  The 
first  belong  more  particularly  to  the  extremities,  and  the 
second  to  the  trunk.  The  third  occur  chiefly  on  the 
head,  the  neck,  the  hands,  the  feet,  and  generally  around 
the  short  bones.  The  form  of  the  muscles,  also,  which 
compose  each  of  these  groups,  varies  very  considerably. 
Most  of  the  exterior  muscles  present  tendinous  or  apo- 
neurotic extremities,  one  of  which  is  termed  the  head,  and 


256  MuscuLAn  system. 

the  other  the  tail;  while  the  intermediate  or  fleshy  part  is 
called  the  belly.  The  belly  of  the  muscle  is  either  formed 
of  a  single  fasciculus,  or  it  consists  of  several  very  distinct 
bundles,  which  are  separated  by  cellular  tissue,  as  in  the 
deltoid,  and  the  glutaeus  maximus;  at  other  times,  the  body 
of  the  muscle  is  interrupted  in  its  length  by  tendinous  fibres, 
which  divide  it  into  several  bellies,  as  in  the  digastricus 
of  the  neck,  and  the  rectus  of  the  abdomen.  In  some  in- 
stances one  of  the  extremities  of  the  muscle  is  divided  into 
two,  and  even  into  three  portions,  as  is  the  case  with  the 
biceps,  and  the  triceps  brachialis  and  cruralis,  &c.  To 
these  muscles  may  be  compared  the  serrated  muscles  of 
the  trunk:  besides  all  these,  there  are  other  muscles  which 
are  simple  throughout  their  whole  extent,  and  have  a  com- 
mon tendinous  extremity,  as  for  instance,  the  latissimus 
dorsi,  and  the  teres  major,  which  are  inserted  by  a  single 
tendon  into  the  os  humeri.  The  muscles  are  always  sym- 
metrical on  each  side  of  the  mesian  line;  the  diaphragm 
forming  the  only  exception  to  this  rule.  They  are  almost 
always  attached  through  the  medium  of  their  fibres  to  the 
periosteum,  to  the  perichondrium,  and  to  the  organs  of  the 
senses;  the  fleshy  fibres  of  the  cutaneous  muscles,  however, 
furnish  an  exception  to  this  rule,  they  being  immediately 
inserted  into  the  dermis,  whose  tissue,  as  we  have  already 
seen,  greatly  resembles  the  fibrous.  The  muscular  fibres 
are  often  inserted  into  the  membranous  prolongations 
which  are  sent  between  the  muscles  by  the  aponeurotic 
envelopes. 

Structure. — The  bundles  and  fasciculi  which  compose 
the  muscles  are  much  more  evident  in  the  exterior  than 
in  the  interior  muscles;  the  fasciculi  of  some  of  the  former 
are  often  so  distinct  and  voluminous  that  one  might  consi- 
der them  as  so  many  muscles.  The  muscular  fibres  pass 
in  various  directions,  being  sometimes  parallel  with  each 
other,  or  in  radiating  lines,  &c.  In  the  first  instance,  the 
fibres  unite  and  present  a  straight  direction,  or  they  pass 


MUSCULAR   SYSTEM.  257 

obliquely,  either  between  two  aponeuroses  which  are  spread 
upon  the  muscle  in  part  or  in  whole,  or  upon  a  tendon  that 
is  first  concealed  in  the  interior  of  the  muscle,  which  often 
presents  in  its  free  part  the  appearance  of  the  plume  of  a 
feather,  either  upon  one  or  both  sides:  hence  the  names  of 
semi-penniform  and  penniform  muscles.  It  would  be 
foreign  to  our  subject  to  point  out  the  different  relations 
which  exist  between  the  muscular  fibres,  or  between  them 
and  their  tendinous  parts;  they  are  details  which  belong  to 
descriptive  anatomy:  we  shall  only  observe  that  the  adhe- 
sion of  the  muscular  fibres  with  the  tendons  is  very  firm 
and  intimate.  The  quantity  of  the  cellular  tissue  of  the 
muscles  is  in  direct  ratio  with  their  volume,  the  size  of  the 
fasciculi,  and  the  interstices  which  separate  them.  In  the 
general  observations  of  the  muscular  system  we  have  al- 
ready seen  the  relations  which  exist  between  the  vascular 
system  and  the  muscles,  and  it  only  remains  to  observe, 
that  their  nerves  are  extremely  numerous,  and  are  derived 
chiefly  from  the  spinal  marrow,  and  the  medulla  oblongata; 
though  some  of  them,  as  the  muscles  of  the  neck  and  pelvis, 
are  furnished  with  filaments  from  the  ganglionic  nerves. 

Physical  properties. — The  colour  of  the  voluntary  mus- 
cles, as  every  body  knows,  is  of  a  deep  red.  The  density 
and  power  of  resistance  of  these  organs  are,  as  is  supposed 
by  anatomists,  in  direct  ratio  with  the  number  of"  their 
fibres,  and  exceed  those  of  the  muscles  of  organic  life,  &c. 
Vital  properties  and  functions. — The  sensibility  of  the 
voluntary  muscles  is  scarcely  observable  in  the  healthy 
state*:  they  contract  with  much  force  and  rapidity  under 
the  influence  of  the  encephalic  action;  and  when  they  are 
rem&ved  from  this  influence,  they  may  still  be  excited  to 
contract  by  the  stimulus  of  galvanism.  The  attitude  and 
movements  of  the  skeleton,  the  motions  of  the  organs  of 
the  senses,  of  the  skin,  the  voice,  of  speech,  and  degluti- 
tion, the  retention  and  expulsion  of  the  excrementitial  mat- 
ters, are  all  the  result  of  muscular  contractions.  These 
34 


258  MUSCULAR   SYSTEM. 

movements  are  either  simple  or  compound:  they  are  sim- 
ple when  they  take  place  in  the  direction  of  the  contrac- 
tion; compound  when  the  muscles  which  produce  them 
have  two  or  more  different  directions. 

The  general  terms  of  congeners  and  antagonists,  are 
applied  to  the  flexors  and  extensors,  the  adductors  and  ab- 
ductors, and  to  the  elevator  and  depressor  muscles,  &c.  We 
generally  observe  different  degrees  of  power  between  the 
antagonist  muscles,  which  can  only  be  studied  in  those 
which  perform  the  motions  of  flexion  and  extension.  Since 
the  time  of  Borelli,  these  differences  have  been  considered 
as  being  advantageous  to  the  extensors;  but  it  appears  that 
this  opinion  is  correct  only  with  respect  to  some  parts  of  the 
body,  as  for  instance,  the  superior  extremities.  In  the  dis- 
position of  the  muscles  there  exist  some  very  important  cir- 
cumstances, which  render  it  necessary  that  there  should  be 
a  considerable  force  on  their  part'in  order  to  produce  mo- 
tion; these  are,  1st,  their  levers  of  the  third  kind;  2d,  the 
very  acute  angle  which  they  generally  form  by  their  in- 
sertion into  the  apophyses,  or  into  the  extremities  of  the 
bones;  3d,  the  resistance  of  the  antagonist  muscles.  We 
shall  not  include  under  these  circumstances  the  obliquity 
of  the  fibres  with  respect  to  the  tendons  into  which  they 
are  inserted,  since  this  obliquity  increases  the  number  of 
fibres,  and  amply  compensates  for  the  loss  which  each  of 
them  sustains:  as  to  the  frictions  of  the  tendons  and  of  the 
articular  surfaces,  they  are  facilitated  by  the  presence  of 
the  sheaths,  and  of  the  synovial  membranes,  in  such  a  man- 
ner, that  they  can  scarcely  be  considered  as  obstacles  to  be 
overcome  by  the  muscular  power.  In  relation  to  the  first 
two  circumstances  which  we  have  just  presented  as  unfa- 
vourable to  the  muscular  power,  it  may  be  observed;  1st, 
that  if  the  levers  of  the  third  kind  are  more  difficult  to 
move,  they  are  the  most  favourable  to  the  extent  and  ra- 
pidity of  motion;  2d,  that  the  facility  of  motion  is  confined 
to  the  form  of  the  body,  and  that  this  form  would  be  very 


MUSCULAR  SYSTEM.  259 

unfavourable  to  locomotion,  if  the  muscles  were  attached 
to  the  bone  at  a  right  angle:  we  perceive,  moreover,  how 
the  extent  of  motion  would  be  impaired  by  such  an  ar- 
rangement. 


section  3. 

Of  the  Interior  Muscles. 

Synonyma:  Hollow  muscles,  involuntary  muscles,  muscles  of  vegetative 
functions,  muscles  of  organic  life. 

Definition. — The  system  of  the  interior  muscles  com- 
prehends the  fleshy  parts  which  enter  into  the  structure  of 
the  organs  of  the  involuntary  functions:  these  parts  are,  the 
heart  and  the  planes  of  the  muscular  fibres  which  enter  into 
the  composition  of  the  teguments  of  the  gastro-pulmonary 
and  the  genito- urinary  passages. 

Situation. — All  the  interior  muscles  are  situated  deep- 
ly, and  belong,  with  the  exception  of  the  heart,  to  the  in- 
ternal tegumentary  system. 

Volume,  form  and  disposition. — The  volume  and  form 
of  these  fleshy  parts  generally  depend  upon  those  of  the 
hollow  organs,  to  the  structure  of  which  they  contribute. 
They  form  muscular  laminae  which  vary  in  thickness,  and 
serve  to  strengthen  the  internal  membranes  of  the  organs 
to  which  we  have  just  alluded.  These  laminae,  which  are 
very  thin  and  few  in  the  digestive  canal  and  the  urinary 
bladder,  are  more  numerous  and  thick  in  the  heart,  are  al- 
ways interlaced  with  each  other,  and  are  generally  circu- 
lar: in  the  oesophagus  and  the  large  intestines  they  are 
longitudinal  and  intersect  the  first,  which  are  exterior  to 
them,  at  a  nearly  right  angle. 

Structure. — The  fibres  which  compose  the  muscles  of 
organic  life  are  sometimes  interlaced;  sometimes  in  juxta- 
position and  united  in  flattened  fasciculi:  in  this  case  they 
sometimes  form  almost  complete  rings,  as  may  be  observ- 


260  MUSCULAR  SYSTEM. 

cd  in  the  greatest  part  of  the- intestines.  In  general,  these 
fibres  are  short;  those  even  which  compose  the  longitudi- 
nal fasciculi  of  the  oesophagus  and  the  large  intestines,  far 
from  having  the  length  of  these  organs,  terminate  after  a 
short  course,  to  give  way  to  others:  they  are  more  or  less 
distinct  according  to  the  organ  that  is  examined;  those 
of  the  uterus  being  only  slightly  manifest  during  pregnan- 
cy. The  tendinous  parts  of  the  interior  muscles  occur  only 
in  the  heart,  at  the  extremities  of  its  columnar  carneae,  at 
the  entrance  of  its  cavities,  and  in  the  auriculo-ventricular 
valves;  the  fibres  of  the  other  interior  muscles  terminate  in 
the  submucous  cellular  tissue,  which  we  have  already  de- 
scribed in  the  first  chapter  of  this  manual. 

The  interior  muscles  present  but  little  cellular  tissue: 
their  vessels  appear  to  be  more  numerous  than  those  of  the 
exterior  muscles;  but,  as  has  been  already  observed,  the 
vascular  branches  which  penetrate  into  their  tissue  should 
not  all  be  regarded  as  belonging  to  these,  for  the  most  of 
them  are  distributed  to  the  internal  teguments.  The  nerves 
of  these  are  less  numerous  than  those  of  the  preceding 
muscles:  most  of  them  are  derived  from  the  ganglia,  and 
anastamose  in  some  of  the  organs  with  the  cerebro-spinal 
nerves, — which  is  observed  in  the  oesophagus,  the  stomach, 
the  rectum  and  the  urinary  bladder. 

Physical  characters. — The  muscular  fibres  which  cover 
the  internal  tegument  are  of  a  pale  grayish  appearance; 
those  of  the  heart,  however,  are  of  a  deeper  red  than  those 
of  the  voluntary  muscles.  Bichat  thought  that  the  muscu- 
lar fibres  of  organic  life  were  more  resisting  than  those  of 
animal  life;  but  the  contrary  appears  to  be  the  more  proba- 
ble, though  if  there  be  any  difference  in  this  respect,  it 
has  not  yet  been  proved. 

Vital  properties  and  functions. — The  sensibility  of  the 
involuntary  muscles  is  very  obscure,  and  can  with  difficul- 
ty be  appreciated  and  distinguished  from  that  of  the  tissues 
with  which  they  are  connected.   Harvey  has  cited  the  case 


MUSCULAR  SYSTEM.  261 

of  a  man,  whose  heart,  being  exposed  in  consequence  of  a 
caries  of  the  sternum,  could  be  irritated  without  pain  to  the 
patient.  Bichat  supposed  that  the  first  sensation  of  hunger 
results  in  part  from  the  long  continued  state  of  contraction 
of  the  muscular  fibres  of  the  stomach.  The  contractions  of 
the  muscles  of  organic  life  are  physiologically  determined 
by  the  contact  of  certain  agents,  such  as  the  blood  for  the 
heart,  the  aliments,  the  chyme,  the  chyle,  and  the  excre- 
mentitial  remains  for  the  muscular  planes  of  the  digestive 
canal,  and  the  urine  for  those^of  the  bladder:  it  ought  to  be 
observed,  that  these  different  substances  stimulate  the  or- 
gans to  which  we  have  just  alluded,  only  through  the  me- 
dium of  the  mucous  or  vascular  tunic  which  covers  them. 
These  contractions  may  also  be  produced  by  mechanical 
stimulants;  galvanism,  on  the  contrary,  operates  with  diffi- 
culty, while  we  recollect  with  what  facility  it  unfolds  the 
irritability  of  the  voluntary  muscles.  A  great  number  of 
morbid  states  of  the  economy  determine  or  accelerate  sym- 
pathetically the  muscular  contractions  of  the  heart  and  of 
the  submucous  fleshy  planes;  but  more  frequently  those  of 
the  first.  Violent  moral  affections  give  rise  to  the  same 
result;  but,  on  the  other  hand,  the  muscles  of  which  we 
are  speaking  are  more  or  less  independent  of  the  ence- 
phalic action:  we  have  no  power  of  suspending  the  con- 
tractions of  the  heart,  though  Bayle,  it  is  said,  had  this 
faculty,  and  Cheyne  refers  to  a  similar  case;  nor  can  we  by 
the  direct  act  of  our  will,  contract  our  alimentary  canal; 
and  we  can  very  readily  explain,  the  influence  of  this  last 
upon  the  urinary  and  fecal  excretions,  by  that  which  it  ex- 
ercises upon  the  exterior  muscles  which  assist  in  its  func- 
tions. Notwithstanding  this  independence,  we  find  that 
it  is"  not  absolute  in  many  diseases  where  the  cerebrospi- 
nal centre  is  injured,  without  the  muscles  of  organic  life  be- 
ing affected,  and  that  many  affections  of  the  encephalon  and 
spinal  marrow  paralyse  more  or  less  promptly  the  organs 
of  which  we  are  treating:  this  is  particularly  the  case  with 


262  MUSCULAR  SYSTEM. 

the  urinary  bladder  and  the  rectum,  on  account  of  the  nerves 
which  they  receive  from  the  spinal  marrow;  so  that  when 
this  is  injured,  it  gives  rise  to  paraplegia,  occasioning  most 
frequently  a  simultaneous  paralysis  of  these  parts. 

The  contractions  of  the  interior  muscles  have  for  their 
object  the  contraction  and  shortening  of  the  hollow  organs 
of  which  they  form  a  part:  the  variety  which  is  observed  in 
the  direction  of  their  fibres,  is  necessary,  in  order  that  this 
contraction  may  accommodate  itself  to  the  form  of  these  or- 
gans, and  take  place  in  every  direction.  From  this  disposi- 
tion, the  solids  or  fluids  which  are  contained  in  the  organs 
just  alluded  to,  receive  a  motory  impression,  either  for  the 
purpose  of  propelling  these  substances  from  one  part  to 
another,  or  to  expel  them  from  the  economy.  The  interior 
muscles  have  no  antagonists  that  may-be  compared  to  those 
of  the  exterior  muscles;  though  we  may,  in  some  measure, 
consider  as  such:  1st,  the  foreign  substances  which  distend 
the  parietes  of  the  hollow  organs,  of  which  the  interior 
muscles  form  a  part;  2d,  the  different  portions  of  the  hol- 
low organs  with  respect  to  each  other:  for  instance,  the 
auricles  of  the  heart  with  respect  to  its  ventricles,  the  first 
being  at  their  height  of  contraction  when  the  second  are  at 
their  minimum  of  relaxation,  and  vice  versa;  the  same  also 
obtains  with  respect  to  the  neck  of  the  uterus  and  of  the 
urinary  bladder  in  relation  to  the  bodies  of  these  organs; 
3d,  the  longitudinal  fibres  of  the  digestive  canal  with  re- 
spect to  circular  fibres,  the  contraction  of  the  first  giving 
rise  to  the  elongation  of  the  second;  4th,  sometimes  the 
voluntary  muscles,  as  for  example,  the  sphincters  of  the 
anus  and  the  bladder  with  respect  to  the  muscular  fibres  of 
these  organs:  indeed,  the  latter  are  relaxed  while  the  for- 
mer contract.  In  some  instances,  also,  the  exterior  mus- 
cles act  as  congeners  of  the  interior;  thus,  during  vomiting, 
the  act  of  defecation,  of  urinary  excretion,  and  of  parturi- 
tion, the  abdominal  muscles  contract  simultaneously  with 
the  stomach,  the  rectum,  the  bladder  and  the  uterus. 


MUSCULAR  SYSTEM.  263 

Bibliography  of  the  Muscular  System. 

The  general  treatises  already  cited. 
Proschaska.  De  carne  musculari  tractatus  anat.  physiol. 

in  op.  minor.;  pars  I.  Viennae,  1820. 
Privost  et  Dumas.  Memoire  sur  les  phenomenes  qui  ac- 

compagnent  la  contraction  de  la  fibre  musculaire;  dans 

Journal  dephysiologie  experementale,  t.  Ill, p.  301 — 339. 
Dutrochet.  Observations  sur  la  structure  intime  des  sys- 

temes  nerveux  et  musculaires,  et  sur  le  mecanisme  de  la 

contraction  chez  les  animaux;  dans  ses  Recherches  anat. 

et  physiol.  sur  la  structure  intime  des  vegetaux  et  des 

animaux,  et  sur  leur  mobilite.  Paris,  1824. 
Haller.  Mem.  sur  la  nature  sensible  et  irritable  des  parties 

Hu  corps  humain.   Lausanne,  1756 — 1759. 
De  partibus  corp.  humani  irritab.;  in  Comm.  Gotting. 

Tom.  II  et  in  Nov.  Comm.  Gotting.  Tom.  IV. 
TVeber.  De  initiis  ac  progr.  doctrinse  irritabilitatis.  Hallse, 

1783. 
Borelli.  De  motu  animalium.  Leyde,  1500. 
Barthez.  NouVelle  mecanique  des  mouvemens  de  l'homme. 

Carcassonne,  1798. 
Roulin.  Recherches  sur  les  mouvemens  et  les  attitudes  de 

l'homme;  dans  Journal  de  physiol.  experim.  vol.  I  et  II. 
Rites.  Diet,  des  sciences  medicales;  art.  Muscle,  Muscu- 

laire  et  Myologie. 
G.  Sedillot.  Mem.  sur  la  rupture  muscul.;  dans  Mem.  et 

prix  du  la  Soc.  de  med.  de  Paris,  1817. 
Hausbrandt.  Dissert,  luxationis  sic  dictse  muscularis  refu- 

tationem  sistens.  Berolini,  1814. 
Fr.  Schnell.  De  natura  reunionis  musculor.  vulneratorum. 

Tubingse,  1804. 


APPENDIX, 


CONTAINING    AN 


ACCOUNT  OF  THE  ACCIDENTAL  TISSUES. 


To  complete  the  history  of  the  anatomy  of  the  tissues, 
it  remains  only  to  speak  of  those  which  are  developed  ac- 
cidentally. The  accidental  tissues  are  divided  into  those 
which  have  more  or  less  resemblance  to  the  natural  tissues, 
and  into  those  which  can  not  be  referred  to  any  of  the  tis- 
sues of  the  healthy  organs.  The  first  constitute  either  the 
true  accidental  productions  or  simple  transformations;  and, 
as  we  have  already  had  occasion  to  speak  of  the  sys- 
tems to  which  they  belong,  we  shall  at  present  treat  only 
of  those  which  recede  from  the  type  of  the  normal  organic 
formations.  From  the  fact,  that  each  of  these  tissues  varies 
according  to  the  part  where,  and  the  time  in  which  it  is  ex- 
amined, and  also  from  the  fact  that  they  often  bear  very 
delicate  shades  of  resemblance  to,  and  are  often  combined 
with,  other  tissues,  authors  have  given  very  different  clas- 
sifications, which  it  would  be  superfluous  to  enumerate  on 
the  present  occasion.  Confining  our  attention  to  the  mor- 
bid tissues  that  have  been  most  generally  admitted,  and 
are  the  best  characterized,  we  shall  successively  describe 
the  tuberculous  productions,  schirrus,  cancer  or  the  en- 
cephaloid  substance  of  M.  Laennec,  and  the  melanotic  sUb- 


appendix.  265 

stance.*  But  before  entering  into  the  particular  history  of 
each  of  these,  we  shall  point  out,  in  a  cursory  manner,  their 
general  characters,  and  the  principal  notions  that  have  been 
advanced  with  respect  to  their  cause  and  mode  of  develop- 
ment. 

The  morbid  tissues  may  be  developed  in  every  part  of  the 
system,  but  they  are  more  frequent  in  those  parts  which 
possess  a  considerable  degree  of  vascularity.  They  occur 
most  frequently  in  a  single  point,  though  sometimes  they 
exist  in  several  simultaneously.  The  relations  of  situation 
of  these  tissues  with  the  organs,  may  be  referred  to  two 
kinds;  in  one  they  occupy  the  interstices  of  the  substance 
of  the  organ,  which  increases  in  size,  and  its  substance, 
crowded  and  compressed  by  the  presence  of  the  morbid 
production,  decays  and  disappears.  In  the  second  kind, 
they  are  formed  on  the  exterior  of  the  organ  which  they 
displace  or  destroy  by  compression,  and  finally,  as  in  the 
preceding  case,  occupy  its  place. 

By  some  authors  these  morbid  productions  are  consider- 
ed as  degenerations  of  the  normal  tissues;  while  others 
profess,  on  the  contrary,  that  they  constitute  new  produc- 
tions, which  are  developed  amongst  the  natural  tissues. 
M.  Meckel,  amongst  others,  admits,  that  by  an  aberration 
of  the  nutritive  process,  analogous  to  inflammation,  the 
organs  become  the  seat  of  an  effusion  of  albuminous  fluid, 
which  becomes  imperfectly  organised  and  assumes  the  dif- 
ferent forms  of  the  preternatural  tissues.  M.  Broussais  also 
attributes  the  production  of  these  accidental  formations  to 
inflammation  of  the  capillaries,  especially  to  that  of  the 
lymphatics;  Bayle  and  Laennec,  on  the  contrary,  regard 
this  phenomenon  as  the  result  of  a  morbid  individual  dia- 
thesis; but  this  opinion  is  supported  by  but  few  persons,  the 

*  The  other  accidental  tissues  admitted  by  Laennec,  viz.  cirrhosis, 
sclerosis,  and  the  squamous  tissue,  do  not  appear  to  have  been  hitherto 
sufficiently  studied,  to  be  described  with  precision. 
35 


266  APPENDIX. 

greater  number  of  anatomists  and  pathologists  embracing 
the  theories  of  MM.  Broussais  and  Meckel. 

The  accidental  tissues,  which  have  no  analogy  with  those 
of  the  healthy  system,  do  not,  in  general,  present  any  ap- 
pearance of  texture,  though  most  of  them  contain  blood- 
vessels and  traces  of  cellular  tissue.  In  proportion  as  they 
become  appreciable,  their  consistence  undergoes  inverse 
changes  of  those  which  are  experienced,  in  this  respect, 
by  the  normal  tissues;  that  is,  instead  of  augmenting,  their 
consistence  progressively  diminishes,  so  much  sb,  that 
these  tissues,  though  sufficiently  hard  in  their  first  crude 
stage,  become  soft,  and  finally,  even  fluid;  they  have  a  ten- 
dency to  escape  from  the  system,  and  exist  only  tempora- 
rily: instead  of  contributing  to  some  function,  they  at  first, 
mechanically  impede  the  action  of  the  neighbouring  organs 
or  of  those  into  which  they  are  infiltrated,  often  produce 
inflammation,  and,  subsequently,  in  their  stage  of  decom- 
position, cause  general  and  serious  disorders,  particularly 
emaciation  and  hectic  fever,  the  precursors  of  a  more  or 
less  speedy  death.  At  this  stage,  also,  the  productions  of 
which  we  are  speaking,  have  a  great  tendency  to  become 
numerous,  and  are  developed,  sometimes,  either  simulta- 
neously, or  successively  in  different  parts,  so  that  the  sys- 
tem appears  to  be  the  seat  of  a  general  infection. 


article  1. 

Of  Tubercles, 

Tubercles  are  homogeneous  case i form  productions,  which 
are  either  infiltrated  into  the  areolae  of  our  organs,  or  are 
united  in  rounded  masses.  They  occur  chiefly  in  the  lungs, 
in  the  tissue  of  the  lymphatic  ganglia  (scrofulous  tubercles,) 
in  the  cellular  tissue,  on  the  surface  of  the  serous  and  the 
mucous  membranes;  in  fact,  there  is  no  organ  in  the  body 
that  may  not  be  affected  with  them.   The  tuberculous  sub- 


\ 


APPENDIX.  267 

stance  is,  at  first,  in  a  fluid  state,  and  of  a  whitish  appear- 
ance; but  it  gradually  acquires  more  and  more  consistence, 
becomes  yellow  and  assumes  the  aspect  of  cheese,  consti- 
tuting what  is  called  its  stage  of  crudity:  at  this  period, 
the  tubercle  is  often  enveloped  by  a  soft  membrane  which 
is  subject  to  various  changes.  Such  is  the  stage  of  devel- 
opment of  the  tuberculous  masses.  They  have  neither 
vessels,  nor  cellular  tissue,  in  a  word,  no  trace  of  organi- 
zation. After  some  time,  they  undergo  a  softening,  which 
begins  at  their  centre  and  extends  gradually  towards  their 
circumference:  the  tubercles  are  now  reduced  efther  to  an 
opake,  yellowish,  homogeneous,  semi-fluid  substance,  or 
they  are  observed  in  the  form  of  flocculi,  which  resemble 
the  cheesy  substance  of  milk.  In  this  stage,  the  tubercu- 
lous substance  leaves  the  point  in  which  it  was  collected, 
opens  a  passage  for  its  escape  from  the  system,  and  the 
cavity  which  it  occupied  often  disappear?  in  consequence 
of  the  approximation  and  adhesion  of  its  parietes:  in  other 
cases,  however,  the  tuberculous  matter  remains,  and  the  pa- 
rietes, which  are  ordinarily  formed  by  the  new  membrane 
which  serves  as  a  cyst  to  the  tubercle,  continue  to  secrete 
puriform  matter,  or  this  membrane,  which  is  at  first  some- 
whatanalogous  by  its  organization  to  the  mucous  teguments, 
becomes  cartilaginous  or  even  osseous;  a  case  of  which  has 
been  lately  reported  by  M.  Laennec,  to  the  Royal  Acade- 
my of  Medicine. 

Bayle  regarded  the  tubercles  as  a  production  sui  generis, 
different  from  the  grayish  transparent  miliary  granulations, 
of  which  he  has  left  an  excellent  description.  Laennec, 
admitting  the  peculiar  nature  of  tubercles,  and  attributing 
them,  in  the  same  manner  as  Bayle,  to  a  peculiar  individu- 
al diathesis,  disagrees  with  this  author  in  considering  the 
miliary  granulations  as  the  first  stage  of  development  of 
the  tuberculous  masses.  M.  Broussais  does  not  separate 
these  productions,  and  asserts  that  they  consist  in  an  alter- 
ation of  the  the  lymphatic  ganglia,  produced  in  conse- 


26S  APPENDIX. 

quence  of  inflammation.*  M.  Andral,  the  younger,  has 
been  led,  after  an  attentive  examination  of  pulmonary  tu- 
bercles and  granulations,  both  in  the  human  subject  and  in 
the  horse,  and  after  a  minute  dissection  of  the  lobules  of  the 
lungs,  to  conclude:  1st,  that  the  granulations  of  Bayle  are 
not  incipient  tubercles,  but  portions  of  the  lobules  of  the 
lungs,  insulated  and  inflamed:!  2d,  that  the  pulmonary  tu- 
bercles are  not  composedof  a  tissue, since  they  do  notpossess 
the  anatomical  characters;  3d,  that  they  are  the  product  of 
a  morbid  secretion,  preceded  by  an  active  sanguineous  con- 
gestion, which  does  not  necessarily  constitute  inflamma- 
tion; 4th,  that  it  is  probable,  but  has  not  been  proved,  that 
the  lymphatic  ganglia  of  the  lungs  are  often  the  seat  of 
tubercles,  (the  lymphatic  vessels  of  the  lungs  and  of  other 
organs  sometimes  contain  a  substance  which  appears  to  be 
identical  with  the  tuberculous  matter:)  5th,  that  tubercles 
occur  in  several  of  the  tissues  which  compose  the  lungs.. 


article  2. 

Of  Schirrus. 

Schirrus,  which  is  often  confounded  under  the  name  of 
encephaloid  cancer,  is  a  very  hard  tissue,  of  a  whitish  or 
bluish  appearance,  and  is  usually  presented  under  the  form 
of  irregular  masses.  It  is  most  frequently  observed  in  the 
neck  of  the  uterus,  the  pyloric  orifice  of  the  stomach,  and 
in  the  glands;  but  there  are  few  organs  which  may  not  be 
its  seat.  In  its  state  of  crudity,  the  schirrous  tissue  is  of 
the  consistence  of  fibro-cartilage,  and  grates  under  the 
scalpel.  By  examining  its  texture,  we  may  observe  traces 
of  the  cellular  and  the  fibrous  tissues,  but  seldom  any  ves- 

*  Morton  and  Portal  had  already  considered  pulmonary  tubercles  as 
engorged  lymphatic  ganglia. 

|  When  the  lymphatic  ganglia  are  inflamed,  they  often  assume  the 
physical  characters  of  these  granulations. 


APPENDIX.  269 

sels;  interiorly,  it  is  often  cellular  and  presents  regular 
radii  like  those  of  the  turnip.  This  tissue  often  becomes 
softened,  and  is  converted  into  a  gelatinous  or  syrup-like 
substance,  which  is  of  a  white,  transparent  appearance,  or 
of  a  reddish,  yellowish,  or  greenish  gray  colour.  The 
schirrous  tissue  presents  many  varieties,  and  amongst 
others,  those  which  Mr.  Abernethy  has  distinguished  by 
the  names  of  the  tuberculous,  the  mammary,  and  the  pan- 
creatic sarcoma.  The  first  is  distinguished  from  schirrus, 
properly  so  called,  by  its  lobular  form. 


article  3. 
Of  Encephaloid  or  cerebriform  Cancer. 

The  tissue  to  which  M.  Laennec  has  applied  the  name 
of encephaloid substance,  is  one  of  those  which  pathologists 
designate  under  the  name  of  cancer,  and  which  has  been 
improperly  called  fungous  inflammation  (Burns,)  fungous 
hematodes  (Hey  and  Wardrop,)  and  medullary  sarcoma 
(Abernethy.)  This  tissue  is  often  found  in  the  uterus,  the 
ovaries,  the  testicles,  the  mammas,  the  brain;  and,  in  fact, 
in  every  organ.  It  is  presented  under  the  form  of  lobular 
masses  with  convolutions  like  those  of  the  brain:  these 
masses  are  often  covered,  either  in  part,  or  in  whole,  by 
a  membranous  production,  which  is  connected  to  them  by 
a  very  loose,  vascular  substance,  and  often  acquires  the 
consistence  of  cartilage.  In  some  cases,  the  cerebriform 
substance  is  infiltrated  into  the  tissue  of  the  organs,  espe- 
cially in  the  uterus. 

In  its  state  of  crudity,  the  encephaloid  tissue  is  of  a  white, 
rose,  or  purple  colour,  either  partially,  or  in  a  uniform 
manner:  it  is  less  consistent  than  schirrus,  and  more  firm 
than  the  substance  of  the  brain.  It  is  traversed  by  blood- 
vessels whose  parietes  are  thin  and  brittle,  and  are  derived 
from  those  which  are  found  in  the  soft  cellular  tissue  which 


270 


APPENDIX. 


covers  the  encephaloid  masses.  Notwithstanding  the  anal- 
ogy which  exists  between  the  encephaloid  and  the  cerebro- 
spinal substances,  both  with  respect  to  their  form  and  their 
apparent  texture,  we  ought  not  to  admit  the  identity  of 
their  tissues. 

The  cerebriform  cancer  soon  becomes  soft,  and  is  con- 
verted into  a  pultacious  substance,  which  is  of  a  reddish 
white,  and  sometimes  grayish  colour,  and  resembles,  in 
some  respects,  the  softened  substance  of  the  brain.  It  often 
happens,  at  this  period,  that  the  vessels  of  the  preternatural 
tissue  break,  and  produce  an  effusion  of  a  considerable 
quantity  of  blood:  under  these  circumstances,  the  fluid  is 
either  discharged  from  the  s)'stem  at  the  moment  of  the 
rupture,  or  it  is  effused  and  operates  in  the  same  manner 
as  the  sanguineous  apoplexies  of  the  cerebral  tissue,  which 
are  not  followed  by  immediate  death.  The  contact  of  the 
air  greatly  accelerates  the  softening  of  the  cerebriform 
substance,  and  its  putrid  decomposition. 


article  4. 
Of  Melanosis. 

This  term  has  been  applied  by  M.  Laennec  to  a  black, 
opake,  preternatural  production,  which  had  already  been 
described  by  several  pathologists  before  him,  and  which 
has  been  considered  by  some  authors  as  a  variety  of  can- 
cer (Meckel),  or  of  tubercles  (Broussais). 

The  melanotic  substance  occurs  either  in  masses,  which 
vary  in  number,  volume,  and  form,  or  it  is  infiltrated  into 
a  great  number  of  organs,  and  particularly  into  the  lungs,  in 
the  cellular,  the  glandular,  and  muscular  systems,  on  the 
surface  of  the  serous  and  the  mucous  membranes,  in  the 
lymphatic  ganglia,  &c.  When  it  occurs  in  masses,  they 
are  connected  to  the  surrounding  tissues  by  cellular  sub- 
stance, which  is  traversed  by  blood-vessels  that  do  not 


APPENDIX.  271 

penetrate  into  the  melanotic  substance:  this  has  no  appearance 
of  texture,  and  receives  considerable  firmness  and  tenacity 
from  the  membrane  which  envelops  it.  By  its  softening, 
which  takes  place  in  a  very  short  time,  the  melanosis  is 
converted  into  a  blackish  deliquescent  substance,  which, 
if  it  be  not  immediately  discharged  from  the  system,  may 
be  absorbed  so  as  to  colour  the  neighbouring  solids  and 
fluids.  This  softening  does  not  influence  the  general  health 
in  so  terrible  a  manner  as  that  of  the  preceding  produc- 
tions. 

The  chemical  analysis  of  the  melanotic  substance  has 
shown  that  it  is  composed  of  a  great  quantity  of  the  fibrin 
and  colouring  matter  of  the  blood,  a  small  quantity  of  albu- 
men, a  considerable  proportion  of  phosphate  of  lime,  of 
the  oxide  of  iron,  of  the  subcarbonate  of  soda,  and  of  the 
chlorate  of  sodium. 

Bibliography  of  Pathological  Anatomy. 

Besides  the  works  cited  above: 
Morgagni.  De  sedibus  et  causis  morborum. 
Bonet.   Sepulchretum,  sive  anat.  pract.  Genevae,  1700. 
Prost.   La  Medecine  eclairee  par  l'ouverture  des  corps. 

Paris,  an  XII. 
J.  Cruveilhier.  Essai  surl'anatomiepathologique  en  gene- 
ral et  sur  les  transformations  et  productions  organiques. 

Paris,  1816. 
P.  Payer.    Sommaire  d'une  Histoire  de  l'Anatomie  pa- 

thologique.  Paris,  1810. 
Bayle.  Sur  les  indurations  blanches  des  organs;  dans  le 

Journal  de  Med.,  torn.  IX,  an  VIII. 
Remarques  sur  les  tubercules;  Journal  de  Corvisart, 

torn.  VI. 

Recherches  sur  la  phtbisie  pulmonaire.  Paris,  1S10. 


Laennec.  Journ.  de  Corvisart,  tome  IX. — Sur  les  me- 
lanoses; dans  Bull,  de  la  Soc.  de  Medecine;  1806. — art. 
Anatomie  pathol.  et  Encephaloide,  du  Diet,  des  Sciences 


272  APPENDIX. 

medicales. — Traite  de  l'auscultation  mediate,  2  fol.  6dit. 

Paris,  1826. 
JBroussais.  Histoire  des  phlegmasies  chroniques,  4vo.  edit. 

Paris,  1S26. 
Maunoir.  Memoire  sur  le  Fongus  nematode.  Paris,  1820. 
Breschet.  Considerations  sur  une  degen6rescence  organ- 

ique  appelee  degenerescence  noire.  Paris,  1821. 
Supplement  aux  Considerations  sur  la  Melanose; 

dans  la  Revue  medicale,  torn.  VII,  p.  79. 
+findral  fils.  Clinique  m6dicale.  Paris,  1824 — 1826. 


THE  END. 


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